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220 questions · 1 auto-graded MCQ + 219 self-marked written.

Question 11 Mark
Write each of the following statements in the form “if-then”
The Bannana trees will bloom if it stays warm for a month.
Answer
If the Banana tree stays warm for a month, then it will bloom.
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Question 21 Mark
Which of the following sentences are statements? Give reasons for your answer.
Today is a windy day.
Answer
The day that is being referred to is not evident from the sentence. Hence, it is not a statement.
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Question 31 Mark
Which of the following sentences are statements? Give reasons for your answer.
Mathematics is difficult.
Answer
This sentence is subjective in the sense that for some people, mathematics can be easy and for some others, it can be difficult. Hence, it is not a statement.
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Question 41 Mark
Write each of the following statements in the form “if-then”
You get a job implies that your credentials are good.
Answer
If you get a job, then your credentials are good.
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Question 51 Mark
Check whether the following pair of statements are negation of each other. Give reasons for your answer.
There exists real numbers x and y for which x + y = y + x.
Answer
This is not the same as statement.
Thus, the given statements are not the negation of each other.
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Question 61 Mark
Which of the following sentences are statements? Give reasons for your answer.
Answer this question.
Answer
It is an order. Therefore, it is not a statement.
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Question 71 Mark
Write the negation of the following statements:
Chennai is the capital of Tamil Nadu.
Answer
Chennai is not the capital of Tamil Nadu.
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Question 81 Mark
Are the following pairs of statements negations of each other:
The number x is a rational number.
The number x is an irrational number.
Answer
The negation of the first statement is “the number x is not a rational number”. This means that the number x is an irrational number, which is the same as the second statement.
Therefore, the given statements are negations of each other.
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Question 91 Mark
Write each of the statements in the form “if p, then q”
r: You can access the website only if you pay a subsciption fee.
Answer
Statement r can be written as follows.
If you can access the website, then you pay a subscription fee.
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Question 101 Mark
Which of the following sentences are statements? Give reasons for your answer.
The square of a number is an even number.
Answer
This sentence is sometimes correct and sometimes incorrect. For example, the square of 2 is an even number. However, the square of 3 is an odd number. Hence, it is not a statement.
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Question 111 Mark
Write the negation of the following statements:
Every natural number is an integer.
Answer
Every natural number is not an integer.
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Question 121 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so.
p: Each radius of a circle is a chord of the circle.
Answer
The given statement p is false.
According to the definition of chord, it should intersect the circle at two distinct points.
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Question 131 Mark
Write each of the statements in the form “if p, then q”
p: It is necessary to have a password to log on to the server.
Answer
Statement p can be written as follows.
If you log on to the server, then you have a password.
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Question 141 Mark
Which of the following sentences are statements? Give reasons for your answer.
The product of (–1) and 8 is 8.
Answer
The product of (–1) and 8 is (–8). Therefore, the given sentence is incorrect. Hence, it is a statement.
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Question 151 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so.
$\text{t}:\sqrt{11}$ 1 is a rational number.
Answer
11 is a prime number and we know that the square root of any prime number is an irrational number. Therefore, $\sqrt{11}$ is an irrational number.
Thus, the given statement t is false.
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Question 161 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so.
q: The centre of a circle bisects each chord of the circle.
Answer
The given statement q is false.
If the chord is not the diameter of the circle, then the centre will not bisect that chord.
In other words, the centre of a circle only bisects the diameter, which is the chord of the circle.
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Question 171 Mark
Write the negation of the following statements:
$\sqrt{2}$ is not a complex number.
Answer
$\sqrt{2}$ is a complex number.
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Question 181 Mark
Rewrite each of the following statements in the form “p if and only if q”
q: For you to get an A grade, it is necessary and sufficient that you do all the homework regularly.
Answer
You get an A grade if and only if you do all the homework regularly.
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Question 191 Mark
Rewrite each of the following statements in the form “p if and only if q”
r: If a quadrilateral is equiangular, then it is a rectangle and if a quadrilateral is a rectangle, then it is equiangular.
Answer
A quadrilateral is equiangular if and only if it is a rectangle.
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Question 201 Mark
Write the negation of the following statements:
q: All cats scratch.
Answer
The negation of statement q is as follows.
There exists a cat that does not scratch.
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Question 211 Mark
Write each of the statements in the form “if p, then q”
q: There is traffic jam whenever it rains.
Answer
Statement q can be written as follows.
If it rains, then there is a traffic jam.
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Question 221 Mark
Write the negation of the following statements:
s: There exists a number x such that 0 < x < 1.
Answer
The negation of statement s is as follows.
There does not exist a number x, such that 0 < x < 1.
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Question 231 Mark
Identify the quantifier in the following statements and write the negation of the statements.
There exists a capital for every state in India.
Answer
The quantifier is “There exists”.
The negation of this statement is as follows.
There exists a state in India which does not have a capital.
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Question 241 Mark
Identify the quantifier in the following statements and write the negation of the statements.
For every real number x, x is less than x + 1.
Answer
The quantifier is “For every”.
The negation of this statement is as follows.
There exist a real number x such that x is not less than x + 1.
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Question 251 Mark
Write the negation of the following statements:
The number 2 is greater than 7.
Answer
The number 2 is not greater than 7.
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Question 261 Mark
Write the negation of the following statements:
r: For every real number x, either x > 1 or x < 1.
Answer
The negation of statement r is as follows.
There exists a real number x, such that neither x > 1 nor x < 1.
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Question 271 Mark
Write each of the following statements in the form “if-then”
A quadrilateral is a parallelogram if its diagonals bisect each other.
Answer
If the diagonals of a quadrilateral bisect each other, then it is a parallelogram.
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Question 281 Mark
State whether the “Or” used in the following statements is “exclusive “or” inclusive. Give reasons for your answer.
To apply for a driving licence, you should have a ration card or a passport.
Answer
Here, “or” is inclusive since a person can have both a ration card and a passport to apply for a driving license.
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Question 291 Mark
Rewrite each of the following statements in the form “p if and only if q”
p: If you watch television, then your mind is free and if your mind is free, then you watch television.
Answer
You watch television if and only if your mind is free.
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Question 301 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so.
s: If x and y are integers such that x > y, then –x < – y.
Answer
x > y
⇒ –x < –y (By a rule of inequality)
Thus, the given statement s is true.
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Question 311 Mark
State whether the “Or” used in the following statements is “exclusive “or” inclusive. Give reasons for your answer.
Sun rises or Moon sets.
Answer
Here, “or” is exclusive because it is not possible for the Sun to rise and the moon to set together.
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Question 321 Mark
Write each of the following statements in the form “if-then”
To get an $A+$ in the class, it is necessary that you do all the exercises of the book.
Answer
If you want to get an $A^+$ in the class, then you do all the exercises of the book.
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Question 331 Mark
Are the following pairs of statements negations of each other:
The number x is not a rational number.
The number x is not an irrational number.
Answer
The negation of the first statement is “the number x is a rational number”.
This is same as the second statement. This is because if a number is not an irrational number, then it is a rational number.
Therefore, the given statements are negations of each other.
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Question 341 Mark
State whether the “Or” used in the following statements is “exclusive “or” inclusive. Give reasons for your answer.
All integers are positive or negative.
Answer
Here, “or” is exclusive because all integers cannot be both positive and negative.
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Question 351 Mark
Which of the following sentences are statements? Give reasons for your answer.
All real numbers are complex numbers.
Answer
All real numbers can be written as a × 1 + 0 × i. Therefore, the given sentence is always correct. Hence, it is a statement.
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Question 361 Mark
Which of the following sentences are statements? Give reasons for your answer.
The sum of 5 and 7 is greater than 10.
Answer
The sum of 5 and 7 is 12, which is greater than 10. Therefore, this sentence is always correct. Hence, it is a statement.
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Question 371 Mark
Which of the following sentences are statements? Give reasons for your answer.
The sides of a quadrilateral have equal length.
Answer
This sentence is sometimes correct and sometimes incorrect. For example, squares and rhombus have sides of equal lengths. However, trapezium and rectangles have sides of unequal lengths. Hence, it is not a statement.
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Question 381 Mark
Write the negation of the following statements:
All triangles are not equilateral triangle.
Answer
All triangles are equilateral triangles.
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Question 391 Mark
Check whether the following pair of statements are negation of each other. Give reasons for your answer.
x + y = y + x is true for every real numbers x and y.
Answer
The negation of statement
is as follows.
There exists real number x and y for which x + y ≠ y + x.
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Question 401 Mark
Which of the following sentences are statements? Give reasons for your answer.
There are 35 days in a month.
Answer
This sentence is incorrect because the maximum number of days in a month is 31. Hence, it is a statement.
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Question 411 Mark
Identify the quantifier in the following statements and write the negation of the statements.
There exists a number which is equal to its square.
Answer
The quantifier is “There exists”.
The negation of this statement is as follows.
There does not exist a number which is equal to its square.
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Question 421 Mark
Which of the following sentences are statements? Give reasons for your answer.
The sum of all interior angles of a triangle is 180°.
Answer
This sentence is correct and hence, it is a statement.
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Question 431 Mark
Write the negation of the following statements:
p: For every positive real number x, the number x – 1 is also positive.
Answer
The negation of statement p is as follows.
There exists a positive real number x, such that x – 1 is not positive.
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Question 441 Mark
Find out the following sentences are statements and which are not. Justify your answer.
All triangles have three sides.
Answer
It is a true declarative sentence because a figure that has three sides is a triangle. Thus, it is a true statement.
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Question 451 Mark
There is a complex number which is not a real number.
Answer
Negation of the given statement:
All complex numbers are real numbers.
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Question 461 Mark
Write the following statements in the form "if p, then q".
Whenever it rains it is cold.
Answer
If it rains, then it is cold.
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Question 471 Mark
Write the negation of the following statements:
p: For every positive real number x, the number (x - 1) is also positive.
Answer
P: For every positive number x, the number (x - 1) is also positive.
P: At least for one positive real number x, the number (x - 1) is not positive.
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Question 481 Mark
Find the component statements of the following compound statements.
Number 7 is prime and odd.
Answer
p: Number 7 is prime.
q: Number 7 is odd.
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Question 491 Mark
Which of the following sentences are statements? Justify.0 is a Complex Number.
Answer
We know that is either true or false but not both simultaneously.
It is true. Hence, it is a statement.
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Question 501 Mark
Which of the following sentences are statements? Justify.A triangle has three sides.
Answer
We know that is either true or false but not both simultaneously.
It is true. Hence, it is a statement.
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Question 511 Mark
Check whether the following statement are true or not:
p: If x and y are odd integers, then x + y is an even integer.
Answer
Let q and r be the statements given by
q: x and y are odd integers.
r: x + y is an even integer.
Then, the given statement is
if q, then r,
Direct Metflod: Let q be true. Then,
q is true.
⇒ x and y are odd integers
⇒ x = 2m + 1, y = 2n + 1 for some integers m, n
⇒ x + y = (2m + 1) + (2n + 1)
⇒ x + y = (2m + 2n + 2)
⇒ x + y = 2 (m + n + 1)
⇒ x + y is an even integer
⇒ r is true.
Thus, q is true ⇒ r is true.
Hence, ''if q, then r'' is a true statement.
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Question 521 Mark
By giving a counter example, show that the following statement is not true.
p: "If all the angles of a triangle are equal, then the triangle is an obtuse angled triangle".
Answer
Consider a triangle ABC with all angles equal. Then each angle of the triangle is equal to 60".
Hence, ABC is not an obtuse angle triangle.
Therefore the following statement is false.
p: "if all the angles of a triangle are equal, then the triangle is an obtuse angled triangle".
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Question 531 Mark
Write down the negation of following compound statement:
35 is a prime number or a composite number.
Answer
Let p: 35 is a prime number.
q: 35 is a composite number.
Then, the negation of the given compound statement is:
~(p v q): 35 is not a prime number and it is not a composite number.
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Question 541 Mark
Show that the statement:
p: "If x is a real number such that $x^3 + x = 0,$ then $x$ is $0"$ is true by.
Direct method.
Answer
Let $q$ and r be the statements given
$q: x$ is a real number such that $x^3 + x = 0.$
$r: x$ is $0.$
Then, $p:$ if $q,$ then $r.$
Direct metrod : Let q be true. Then,
q is true
$\Rightarrow x$ is a real num bar such that $x^3 + x\ 0$
$\Rightarrow x$ is a real num bar such that $x (x^2 + 1) = 0$
$\Rightarrow x = 0$
$\Rightarrow r$ is true.
Thus, $q$ is true $\Rightarrow r$ is true.
Hence, $p$ is true.
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Question 551 Mark
Identify the Quantifiers in the following statement:
There exists a even prime number other than 2.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 561 Mark
Find the component statements of the following compound statements.
Chandigarh is the Capital of Haryana and U.P.
Answer
p: Chandigarh is Capital of Haryana.
q: Chandigarh is Capital of U.P.
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Question 571 Mark
Which of the following sentences are statements? Justify.Where is your bag?
Answer
We know that is either true or false but not both simultaneously.
Since it is a question. Hence, it is not a statement.
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Question 581 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Is the earth round?
Answer
It is an interrogative sentence, so it is not a statement.
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Question 591 Mark
Translate the following statement into symbolic form:
A number is either divisible by 2 or 3.
Answer
p: A number is divisible by 2.
q: A number is divisible by 3.
p v q: A number is either divisible by 2 or 3.
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Question 601 Mark
Write down the converse of following statement:
If a rectangle ‘R’ is a square, then R is a rhombus.
Answer
If the rectangle R is rhombus, then it is square.
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Question 611 Mark
Determine the contrapositive of the following statements:
If x is less than zero, then x is not positive.
Answer
If x is positive, then x is not less than zero.
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Question 621 Mark
All policemen are thieves.
Answer
Negation of the given statement:
There exists a policeman who is not a thief.
Or
At least one policeman is not a thief.
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Question 631 Mark
Are the following pairs of statements are negation of each other:
The number x is not a rational number.
The number x is an irrational number.
Answer
The statements in this pair are not the negation of each other because both statements are the same. Both the statements convey that x is an irrational number.
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Question 641 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false.
57 is divisible by 2 or 3.
Answer
Here the given statement is the form p q which has the truth value T whenever either p or q or both have the truth value T. Hence, it is a true statement and its component statements are
p: 57 is divisible by 2. (False).
q: 57 is divisible by 3. (True).
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Question 651 Mark
Determine the contrapositive of the following statements:
If Mohan is a poet, then he is poor.
Answer
If Mohan is not poor, then he is not a poet.
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Question 661 Mark
Form the biconditional statement p ↔ q, where.
p: A natural number n is odd.
q: Natural number n is not divisible by 2.
Answer
p ⟷ q: A natural number is odd if and only if it is not divisible by 2.
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Question 671 Mark
Write down the contrapositive of the following statement:
If natural number n is divisible by 6, then n is divisible by 2 and 3.
Answer
If natural number ‘n’ is not divisible by 2 or 3, then n is not divisible by 6.
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Question 681 Mark
Give three examples of sentences which are not statements. Give reasons for the answers.
Answer
  1. I won the trophy!
It is an exclamatory sentence, so it is not a statement.
  1. Please fetch me a glass of water.
It is an imperative sentence. In other words, it can be expressed either as a request or as a command. Therefore, it not a statement.
  1. Can you do this work for me?
It is an interrogative sentence, so it is not a statement.
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Question 691 Mark
State the converse and contrapositive of the following statements:
If it is hot outside, then you feel thirsty.
Answer
Converse:
If you feel thirsty, then it is hot outside.
Contrapositive:
If you do not feel thirsty, then it is not hot outside.
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Question 701 Mark
Write down the contrapositive of the following statement:
If it snows, then the weather will be cold.
Answer
The weather will not be cold, if it does not snow.
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Question 711 Mark
Translate the following statement into symbolic form:
Either $x=2$ or $x=3$ is a root of $3 x^2-x-10=0$.
Answer
$\mathrm{p}: \mathrm{x}=2$ is a root of $3 \times 2-\mathrm{x}-10=0$.
$\mathrm{q}: \mathrm{x}=3$ is a root of $3 \times 2-\mathrm{x}-10=0$.
p vq : Either $\mathrm{x}=2$ or $\mathrm{x}=3$ is a root of $3 \times 2-\mathrm{x}-10=0$.
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Question 721 Mark
Which of the following sentences are statements? Justify.$\sin^2\text{x}+\cos^2\text{x}=0$
Answer
We know that is either true or false but not both simultaneously.
It is false. Hence, it is a statement.
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Question 731 Mark
Write the negation of the following simple statement:
Cow has four legs.
Answer
Cow does not have four legs.
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Question 741 Mark
Which of the following sentences are statements? Justify.Every square is a rectangle.
Answer
We know that is either true or false but not both simultaneously.
It is true. Hence, it is a statement.
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Question 751 Mark
Write the following statements in the form "if p, then q".
The game is cancelled only if it is raining.
Answer
If it rains, only then the game is cancelled.
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Question 761 Mark
Find the component statements of the following compound statements.
Chennai is in India and is the capital of Tamil Nadu.
Answer
p: Chennai is in India.
q: Chennai is the Capital of Tamil Nadu.
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Question 771 Mark
Determine the contrapositive of the following statements:
It never rains when it is cold.
Answer
If it rains, it is not cold.
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Question 781 Mark
Write the negation of the following statements:
The earth is round.
Answer
Negation of the given statement:
The earth is not round.
Or
It is not true that the earth is round
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Question 791 Mark
Find the component statements of the following compound statements:
25 is a multiple of 5 and 8.
Answer
The component statements of the given compound statement are:
25 is a multiple of 5.
25 is a multiple of 8.
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Question 801 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Listen to me, Ravi.
Answer
It is an exclamatory sentence. Therefore, it is not a statement.
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Question 811 Mark
Write down the negation of following compound statement:
All real numbers are rationals or irrationals.
Answer
Let p: All real numbers are rationals.
q: All real numbers are irrationals.
Then, the negation of the given compound statement is:
~(p v q): All real numbers are not rational and all real numbers are not irrational.
[~(p v q) = ~p ∧ ~ q]
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Question 821 Mark
Check the validity of the following statements:
p: 100 is a multiple of 4 and 5.
Answer
The statem ant is:
"100 ism ultiple of 4 and 5"
We know that 100 is a multiple of 4 as well as 5. So, p is true statement.
Hence, the statement is true i.e. the statement "p" is a valid statement.
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Question 831 Mark
Find the component statements of the following compound statements:
All rational numbers are real and all real numbers are complex.
Answer
The component statements of the given compound statement are:
All rational numbers are real.
All real numbers are complex.
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Question 841 Mark
Determine the contrapositive of the following statements:
It is necessary to be strong in order to be a sailor.
Answer
If you are not strong, then you cannot be a sailor.
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Question 851 Mark
Identify the Quantifiers in the following statement:
For all real numbers x with $x > 3, x^2$ is greater than $9.$
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.For all.
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Question 861 Mark
Write the negation of the following simple statement:
Area of a circle is same as the perimeter of the circle.
Answer
Area of a circle is not same as the perimeter of the circle.
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Question 881 Mark
Check whether the following statement are true or not:
q: If x, y are integers such that xy is even, then at least one of x and y is an even integer.
Answer
Let r and s be two statements given by
r: xy is an even integer.
s: At least one of x and y is an even integer
Lets be not true. Then,
s is not true
⇒ Both x and y are odd integers
Let x = 2n + 1 and y = 2m + 1 for some integers n and m. Then,
⇒ xy = (2n + 1)(2m + 1) for some integers n and m.
⇒ xy = 4nm + 2(n + m) + 1 for some integers n and m,
⇒ xy is an odd integer
⇒ xy is not an even integer
⇒ -r is true
Thus, -s is trua es -r is true
Hence, the given statement is true.
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Question 891 Mark
Show that the following statement is true "The integer $n$ is even if an only if $n^2$ is even"
Answer
The given statement can be re$-$written as
$"$The necessary and sufficient condition that the integer $n$ is even is $n^2$ must be even$"$
Let $p$ and $q$ be the statements given by
$p:$ the integer $n$ is even.
$q: n^2 $ is even.
The given statement is
$"p$ if and only if $q"$
In order to check its validity, we have to check the validity of the following statements.
  1. $"$If $p,$ then $q"$
  2. $"$if $q,$ then $p"$
Checking the validity of $"$if $p,$ then $q":$
The statement $"$if $p,$ then $q"$ is given by:
"If the integer $n$ is even, then $n^2 $ is even$"$
Let us assume that $n$ is even. Then,
$n = 2m,$ where $m$ is an integer
$\Rightarrow n^2 = (2m)^2$
$\Rightarrow n^2 = 4m^2$^
$\Rightarrow n^2 $is an even integer
Thus, $n$ is even $\Rightarrow n^2 $ is even
$\therefore "$if $p$, then $q"$ is true.
Checking the validity of $"$if $q$, then $p":$
"if $n$ is an integer and $n^2 $ is even, 'then $n$ is even$"$
To check the validity of this statemens, we will use contrapositive method.
So, let $n$ be an odd integer. Then,
$n $ is odd
$\Rightarrow n = 2k + 1$ for some integer $k:$
$\Rightarrow n^2 = (2k + 1)^2$
$\Rightarrow n^2 = 4k^2 + 4k + 1$
$\Rightarrow n^2$  is not an even integer
Thus, $n$ is not even $\Rightarrow n^2$ is not even
$\therefore "$if $q,$ then $p"$ is true.
Hence, $"p$ if and only if $q"$ is true.
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Question 901 Mark
Write the following statements in the form "if p, then q".
It is necessary to be rich in order to be happy.
Answer
If you want to be happy, then you will have to be rich.
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Question 911 Mark
Write the negation of the following statements:
r: There exists a number x such that 0 < x < 1.
Answer
r: There exists a number x such that 0 < x < 1.
r: For every real number x, either x ≤ 0 or x < 1.
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Question 921 Mark
Find out the following sentences are statements and which are not. Justify your answer.
$\text{x}^2+5|\text{x}|+6=0$ has no real roots.
Answer
It is a true declarative sentence, so it is a statement.
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Question 931 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Mathematics is difficult.
Answer
Mathematics could be easy for some people, so this sentence may or may not be true. So, it is not a statement.
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Question 941 Mark
For the following statements, determine whether an inclusive "OR" or exclusive "OR" is used. Give reasons for your answer.
A lady gives birth to a baby boy or a baby girl.
Answer
Exclusive OR because a lady can give a birth to a baby who is either a boy or a girl.
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Question 951 Mark
Write the negation of the following simple statement:
A leap year has 366 days.
Answer
A leap year does not have 366 days.
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Question 961 Mark
Identify the Quantifiers in the following statement:
For all real numbers x and y, xy = yx.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
For all.
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Question 971 Mark
Rewrite the following statements in the form of conditional statement:
2b = a + c, if a, b and c are in A.P.
Answer
q implies p ⇒ If a, b, c are in A.P then 2b = a + c.
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Question 981 Mark
Rewrite the following statements in the form "p if and only if q".
s: If a tumbler is half empty, then it is half full and if a tumbler is half full, then it is half empty.
Answer
The tumbler is half empty if and only if the tumbler is half full.
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Question 991 Mark
Write down the contrapositive of the following statement:
If all three sides of a triangle are equal, then the triangle is equilateral.
Answer
If the triangle is not equilateral, then all three sides of the triangle are not equal.
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Question 1001 Mark
Translate the following statement into symbolic form:
2, 3 and 6 are factors of 12.
Answer
p: 2 is factor of 12.
q: 3 is factor of 12.
r: 6 is factor of 12.
p ∧ q ∧ r: 2, 3 and 6 are factors of 12
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Question 1011 Mark
Find out the following sentences are statements and which are not. Justify your answer.
There are 35 days in a month.
Answer
It is a false assertive sentence, so it is a false statement.
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Question 1021 Mark
Check whether the following pair of statements are negation of each other. Give reasons for your answer.
  1. $a + b = b + a$ is true for every real number $a$ and $b.$
  2. There exist real numbers a and b for which $a + b = b + a.$
Answer
the negation of ​the statements
$a + b = b + a$ is true for every real number $a$ and $b.$
is:
There exist real numbers $a$ and $b$ for which $a + b \neq b + a.$
So, the given statment is of not tha negation of the first statment.
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Question 1031 Mark
Which of the following sentences are statements? Justify.15 + 8 > 23
Answer
We know that is either true or false but not both simultaneously.
It is false. Hence, it is a statement.
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Question 1041 Mark
Rewrite the following statements in the form "p if and only if q".
r: For you to get an A grade, it is necessary and sufficient that you do all the homework regularly.
Answer
You get an A grade if and only if you do all the homework regularly.
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Question 1051 Mark
Write the negation of the following simple statement:
$\sqrt{5}$ is a rational number.
Answer
$\sqrt{5}$ is not a rational number.
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Question 1061 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so:
$\text{t}:\sqrt{11}$ is a rational number.
Answer
False. Because square roots of prime num bars are irrational num bars.
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Question 1071 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false:
All rational numbers are real and all real numbers are not complex.
Answer
The component statements of the given compound statement are:
  1. All rational numbers are real.
  2. All real numbers are not complex.
The compound statement is false because all real numbers are complex. The connective used is "and". So, even if one component statement is false, the compound statement is false.
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Question 1081 Mark
Write the negation of the following statements:Ravish is honest.
Answer
Negation of the given statement:
It is not true that Ravish is honest.
Or
Ravish is not honest
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Question 1091 Mark
Rewrite the following statements in the form of conditional statement:
You will fail, if you will not study.
Answer
p only if q ⇒ If you do not study, then you will fail.
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Question 1101 Mark
Write the negation of the following statements:
Banglore is the capital of Karnataka.
Answer
Negation of the given statement:
It is not true that Bangalore is the capital of Karnataka.
Or
Bangalore is not the capital of Karnataka.
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Question 1111 Mark
Both the diagonals of a rectangle have the same length.
Answer
Negation of the given statement:
Both the diagonals of a rectangle do not have the same length.
Or
Both the diagonals of a rectangle have different lengths.
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Question 1121 Mark
Write down the converse of following statement:
If x is zero, then x is neither positive nor negative.
Answer
If x is nether positive nor negative then x = 0.
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Question 1131 Mark
Identify the Quantifiers in the following statement:For every natural number x, x + 1 is also a natural number.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
For every.
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Question 1141 Mark
Write the negation of the following simple statement:
All similar triangles are congruent.
Answer
There exist similar triangles which are not congruent.
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Question 1151 Mark
Write down the contrapositive of the following statement:
If x and y are negative integers, then xy is positive.
Answer
If xy is not positive integer, then x or y is not negative integer.
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Question 1161 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false:
The sand heats up quickly in the sun and does not cool down fast at night.
Answer
The component statements of the given compound statement are:
  1. The sand heats up quickly in the sun.
  2. Sand does not cool down fast at night.
The compound statement uses "and" as the connective. For the compound statement to be true, both the component statements must be true. The second component statement "Sand does not cool down fast at night" is false. Sand cools down fast at night. Therefore, the compound statement is false.
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Question 1171 Mark
Write down the converse of following statement:
If today is Monday, then tomorrow is Tuesday.
Answer
If tomorrow is Tuesday, then today is Monday.
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Question 1181 Mark
Determine whether the argument used to check the validity of the following statement is correct:
p: "If $x^2$ is irrational, then $x$ is rational"
The statement is true because the number $\text{x}^2=\pi^2$ is irrational, therefore $\text{x}=\pi$ is irrational.
Answer
The argument used to check the validity of the given statement is not correct because it does not produce a contradiction.
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Question 1191 Mark
State the converse and contrapositive of the following statements:
If you live in Delhi, then you have winter clothes.
Answer
Converse:
If you have winter clothes, then you live in Delhi.
Contrapositive:
​If you do not have winter clothes, then you do not live in Delhi.
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Question 1201 Mark
Rewrite the following statements in the form of conditional statement:
The square of a prime number is not prime.
Answer
q is necessary for p ⇒ If any number is prime, then its square is not prime.
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Question 1211 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so:
p: Each radius of a circle is a chord of the circle.
Answer
False. Because, no radius of a circle is its chord.
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Question 1221 Mark
Find the component statements of the following compound statements:
The sky is blue and the grass is green.
Answer
The component statements of the given compound statement are:
The sky is blue.
The grass is green.
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Question 1231 Mark
Negate the following statements:
All the students completed their homework.
Answer
Negation of the given statement:
Some students did not complete their homework.
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Question 1241 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Are all circles round?
Answer
It is an interrogative sentence, so it is not a statement.
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Question 1251 Mark
Write the following statements in the form "if p, then q".
It never rains when it is cold.
Answer
If it is cold, then it never rains.
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Question 1261 Mark
Write down the converse of following statement:
If x : y = 3 : 2, then 2x = 3y.
Answer
If 2x = 3y then x : y = 3 : 2.
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Question 1271 Mark
Find the component statements of the following compound statements.
0 is less than every positive integer and every negative integer.
Answer
p: 0 is less than every positive integer.
q: 0 is less than every negative integer.
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Question 1281 Mark
Which of the following sentences are statements? Justify.y + 9 =7
Answer
We know that is either true or false but not both simultaneously.
y + 9 = 7, here that the value of y is not given. So it is true for y = -2 and false for any other value of y. Hence, it is not a statement.
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Question 1291 Mark
Write the negation of the following simple statement:
2 is not a prime number.
Answer
2 is a prime number.
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Question 1301 Mark
Find the component statements of the following compound statements.
Two lines in a plane either intersect at one point or they are parallel.
Answer
p: Two line is a plane intersect at one point.
q: Two lines in a plane are parallel.
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Question 1311 Mark
Determine the contrapositive of the following statements:
If Ravish skis, then it snowed.
Answer
If it did not snow, then Ravish does not ski.
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Question 1321 Mark
Determine the contrapositive of the following statements:
Only if he does not tire will he win.
Answer
If he tires, then he will not win.
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Question 1331 Mark
Form the biconditional statement p ↔ q, where.
p: A triangle is an equilateral triangle.
q: All three sides of a triangle are equal.
Answer
p ⟷ q: A triangle is an equilateral triangle if and only if all three sides of triangle are equal.
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Question 1341 Mark
For the following statements, determine whether an inclusive "OR" or exclusive "OR" is used. Give reasons for your answer.
To entry a country, you need a passport or a voter registration card.
Answer
Inclusive OR is used because a person can have both passport as well as voter registration card.
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Question 1351 Mark
Determine the contrapositive of the following statements:
Only if Max studies will he pass the test.
Answer
If Max does not study, then he will not pass the test.
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Question 1361 Mark
Rewrite the following statements in the form "p if and only if q".
p: If you watch television, then your mind is free and if your mind is free, then you watch television.
Answer
You watch television if and only if your mind is free.
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Question 1371 Mark
Rewrite the following statements in the form of conditional statement:
You will get a sweet dish after the dinner.
Answer
q if p ⇒ If take the dinner, then you will get sweet dish.
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Question 1381 Mark
Show that the following statement is true by the method of contrapositive
p: "If $x$ is an integer and $x^2$ is odd, then $x$ is also odd"
Answer
Let $q$ and $r$ be the statements given by
$q:$ lf $x$ is an integer and $x^2$ is odd
$r: x$ is an odd integer.
Then, $p:$ " lf $q$, thenr."
If possible, let r be false. Then,
$r$ is false
$\Rightarrow x$ is not an odd integer
$\Rightarrow x$ is an even integer
$\Rightarrow x = (2n)$ for some integer $n$
$\Rightarrow x^2 = 4n^2$ 
$\Rightarrow x^2$​​​​​​​^ is an even integer
$\Rightarrow q$ is false.
Thus, $r$ is false $\Rightarrow q$ is false.
Hence, $p$: "if $q$, then $r$" is a true statement.
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Question 1391 Mark
Show that the statement:
$p: "$If x is a real number such that $x^3 + x = 0,$ then $x$ is $0"$ is true by.
Method of contradition.
Answer
Let $q$ and $r$ be the statements given
$q: x$ is a real number such that $x^3 + x = 0.$
$r: x$ is $0.$
Then, $p:$ if $q$, then $r.$
Metnod of contradiction: If possible, let p be not true. Then,
$p$ is not true
$\Rightarrow $ -pis true
$\Rightarrow -(p \Rightarrow r)$ is true
$\Rightarrow q$ and $-r$ is true
$\Rightarrow x$ is a real number such that $x^3 + x = 0$ and $x = 0$
$\Rightarrow\text{x}=0$ and $\text{x}\not=0$
This a contradiction.
Hence, $p$ is true.
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Question 1401 Mark
Determine the contrapositive of the following statements:
If $x$ is an integer and $x^2$ is odd, then $x$ is odd.
Answer
If $x$ is even, then $x^2$ is even.
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Question 1411 Mark
Write the negation of the following statements:
q: For every real number x, either x > 1 or x < 1.
Answer
q: For every real number x, either x > 1 or x < 1.
q: At least for one real number x, neither x > 1x > 1 nor x < 1x < 1.
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Question 1421 Mark
Write the negation of the following statements:
For every $\text{x}\in\text{N},\text{x}+3<10$
Answer
The Negation of the statement:
For every $\text{x}\in\text{N},\text{x}+3<10$
There exists $\text{x}\in\text{N}$ such that $\text{x}+3\geq10$
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Question 1431 Mark
Some even integers are prime.
Answer
Negation of the given statement:
Some integers are not prime.
Or
No even integer is prime.
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Question 1451 Mark
Find the component statements of the following compound statements:
The earth is round or the sun is cold.
Answer
The component statements of the given compound statement are:
The earth is round.
The sun is cold.
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Question 1461 Mark
Translate the following statement into symbolic form:
Rahul passed in Hindi and English.
Answer
p: Rahul passed in Hindi.
q: Rahul passed in English.
p ∧ q: Rahul passed in Hindi and English.
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Question 1471 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so:
s: If x and y are integers such that x > y, then -x < -y.
Answer
True. Because, for any two integers, if x - y is positive then -(x - y) is negative.
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Question 1481 Mark
Identify the Quantifiers in the following statement:
There exists a triangle which is not an isosceles triangle.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 1491 Mark
Write the negation of the following statements:
It rained on July 4, 2005.
Answer
Negation of the given statement:
It is not true that it rained on July 4, 2005.
Or
It did not rain on July 4, 2005.
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Question 1501 Mark
Find the component statements of the following compound statements.
The number 100 is divisible by 3, 11 and 5.
Answer
p: 100 is divisible by 3.
q: 100 is divisible by 11.
r: 100 is divisible by 5.
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Question 1511 Mark
Identify the Quantifiers in the following statement:
There exists a real number $x$ such that $x^2 + 1 = 0.$
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 1521 Mark
Which of the following sentences are statements? Justify.Sum of opposite angles of a cyclic quadrilateral is 180°
Answer
We know that is either true or false but not both simultaneously.
It is true. Hence, it is a statement.
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Question 1531 Mark
Check the validity of the following statements:
r: 60 is a multiple of 3 or 5.
Answer
The statement is:
r: 60 ism ultiple of 3 or 5
is a com pound statement of the following statements:
p: 60 is multiple of 3
q: 60 is multiple of 5
Suppose q is false. That is, 60 is not a multiple of 5. Clearly p is true.
Thus, if we assume that q is false, then p is true.
Hence, the statement is true i.e. the statement "r" is a valid statement.
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Question 1541 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Two non-empty sets have always a non-empty intersection.
Answer
It is a false assertive sentence. Two non-empty sets with no common elements can have an empty intersection. Therefore, it is a statement.
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Question 1551 Mark
All birds sing.
Answer
Negation of the given statement:
Some birds do not sing.
Or
There exists a bird that does not sing.
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Question 1561 Mark
For the following statements, determine whether an inclusive "OR" or exclusive "OR" is used. Give reasons for your answer.
Students can take Hindi or Sanskrit as their third language.
Answer
Exclusive OR is used because students can opt for either Hindi or Sanskrit as their third language.
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Question 1571 Mark
Write down the converse of following statement:
If all three angles of a triangle are equal, then the triangle is equilateral.
Answer
If the triangle is equilateral, then all three angles of the triangle are equal.
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Question 1591 Mark
Find out the following sentences are statements and which are not. Justify your answer.
The cat pussy is black.
Answer
It is a declarative sentence, which may be true or false but cannot be both at the same time, so it is a statement.
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Question 1601 Mark
Rewrite the following statements in the form of conditional statement:
The unit digit of an integer is 0 or 5 if it is divisible by 5.
Answer
p is sufficient for q ⇒ If an integer is divisible by 5, then its unit digits are 0 or 5.
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Question 1611 Mark
Find out the following sentences are statements and which are not. Justify your answer.
This sentence is a statement.
Answer
Without knowing the sentence, we cannot decide whether it is true or false. So, it is not a statement.
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Question 1621 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Every rhombus is a square.
Answer
It is not true that every rhombus is a square because some rhombi may have all angles other than 90. So, it is a false statement.
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Question 1631 Mark
Write down the converse of following statement:
If S is a cyclic quadrilateral, then the opposite angles of S are supplementary.
Answer
If the opposite angles of a quadrilateral are supplementary, then S is cyclic.
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Question 1641 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so:
r: Circle is a particular case of an ellipse.
Answer
True. Because a circle is an ellipse that has equal axes.
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Question 1651 Mark
Find out the following sentences are statements and which are not. Justify your answer.
The real number x is less than 2.
Answer
We cannot decide whether this sentence is true or false without knowing the value of x. So, it is not a statement.
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Question 1661 Mark
Determine the contrapositive of the following statements:
If she works, she will earn money.
Answer
If she does not earn money, then she will not work.
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Question 1671 Mark
Write down the converse of following statement:
If you go to Agra, then you must visit Taj Mahal.
Answer
If you must visit Taj Mahal, then you go to Agra.
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Question 1681 Mark
Rewrite the following statements in the form of conditional statement:
The square of an odd number is odd.
Answer
If p, then q ⇒ If the number is odd, then its square is odd number.
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Question 1691 Mark
Write down the negation of following compound statement:
6 is divisible by 2 and 3.
Answer
Let p: 6 is divisible by 2.
q: 6 is divisible by 3.
Then, the negation of the given compound statement is:
~(p ∧ q): 6 is not divisible by 2 or it is not divisible by 3
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Question 1701 Mark
Write down the negation of following compound statement:
All prime integers are either even or odd.
Answer
Let p: All prime integers are even.
q: All prime integers are odd.
Then, the negation of the given compound statement is given by ~ (p v q):
All prime integers are not even and all prime integers are not odd.
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Question 1711 Mark
Write the following statements in the form "if p, then q".
There is traffic jam whenever it rains.
Answer
If it rains, then there is a traffic jam.
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Question 1721 Mark
Write the following statements in the form "if p, then q".
It is necessary to have a passport to log on to the server.
Answer
It is necessary to have a passport to log on to the server.
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Question 1731 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false:
$x = 2$ and $x = 3$ are the roots or the equation $3x^2 − x − 10 = 0.$
Answer
The component statements of the given compound statement are:
  1. $x = 2$ is the root or the equation $3x^2 - x - 10 = 0.$
  2. $x = 3$ is the root or the equation $3x^2 - x - 10 = 0.$
The connective used is "and". So, both component statements must be true for the compound statement to be true. The statement $"x = 3x = 3$ is the root or the equation $3x^2 - x - 10 = 0"$ is false. Therefore, the compound statement is false.
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Question 1741 Mark
Which of the following sentences are statements? Justify.Sky is red.
Answer
We know that is either true or false but not both simultaneously.
It is false. Hence, it is a statement.
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Question 1751 Mark
Write the following statements in the form "if p, then q".
You can access the website only if you pay a subscription fee.
Answer
If you pay a subscription fee, then you can access the website.
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Question 1761 Mark
Negate the following statements:
There exists a number which is equal to its square.
Answer
Negation of the given statement:
There exists a number which is not equal to its square.
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Question 1771 Mark
For the following statements, determine whether an inclusive "OR" or exclusive "OR" is used. Give reasons for your answer.
To apply for a driving licence, you should have a ration card or a passport.
Answer
Inclusive OR because a person could have both ration card as well as passport.
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Question 1781 Mark
Identify the Quantifiers in the following statement:
There exists a statement in above statements which is not true.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 1791 Mark
Write the negation of the following simple statement:
Every real number is an irrational number.
Answer
Every real number is not an irrational number.
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MCQ 1801 Mark
Which of the following cannot be the negation of the statement “Everyone in India speaks Hindi”?
  • A
    Not everyone in India speaks Hindi.
  • No person in India speaks Hindi.
  • C
    Someone in India does not speaks Hindi.
  • D
    At least one person in India who does not speaks Hindi.
Answer
Correct option: B.
No person in India speaks Hindi.
Negation of everyone is not everyone. So, negation of the given statement should be “Not everyone in India speaks Hindi”, “Someone in India does not speaks Hindi”, “At least one person in India who does not speaks Hindi”. “No person in India speaks Hindi” cannot be the negation of the given statement as this means no one speaks Hindi which does not means not everyone.
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Question 1811 Mark
Find the component statements of the following compound statements.
A rectangle is a quadrilateral or a 5-sided polygon.
Answer
p: A rectangle is a quadrilateral.
q: A rectangle is a 5-sides polygon.
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Question 1821 Mark
Find the component statements of the following compound statements.
plants use sunlight, water and carbon-dioxide for photosynthesis.
Answer
p: Plants use sunlight for photosynthesis.
q: Plants use water for photosynthesis.
r: Plants use carbon-dioxide for photosynthesis.
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Question 1831 Mark
Write the negation of the following simple statement:
The number 17 is prime.
Answer
The number 17 is not prime.
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Question 1841 Mark
Translate the following statement into symbolic form:
Either x or x + 1 is an odd integer.
Answer
p: x is an odd integer.
q: (x + 1) is an odd integer.
p v q: Either x or (x + 1) is an odd integer.
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Question 1851 Mark
Write the following statements in the form "if p, then q".
It rains only if it is cold.
Answer
If it rains, then it is cold.
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Question 1861 Mark
Translate the following statement into symbolic form:
Students can take Hindi or English as an optional paper.
Answer
p: Students can take Hindi as an optional paper.
q: Students can take English as an optional paper.
p v q: Students can take Hindi or English as an optional paper.
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Question 1871 Mark
Show that the statement:
$p: "$If x is a real number such that $x^3 + x = 0, $ then $x$ is $0"$ is true by.
Method of contrapositive
Answer
Let $q$ and $r$ be the statements given
$q: x$ is a real number such that $x^3 + x = 0.$
$r: x$ is $0.$
Then, $p:$ if $q$, then $r.$
Method of contrapositive: Let $r$ be not true. Then,
$r$ is not true.
$\Rightarrow\text{x}\not=0,\ \text{x}\in\text{R}$
$\Rightarrow\text{x}(\text{x}^2+1)\not=0,\ \text{x}\in\text{R}$
$\Rightarrow q$ is not true
Thus, $-r = -q.$
Hence, $p : q \Rightarrow r$ is true.
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Question 1881 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false:
To enter into a public library children need an identity card from the school or a letter from the school authorities.
Answer
The component statements of the given compound statement are:
  1. To enter into a public library, children need an identity card from the school.
  2. To enter into a public library, children need a letter from the school authorities.
The compound statement is true because both component statements are true.
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Question 1891 Mark
Rewrite the following statements in the form "p if and only if q".
q: If a quadrilateral is equiangular, then it is a rectangle and if a quadrilateral is a rectangle, then it is equiangular.
Answer
A quadrilateral is a rectangle if and only if it is equiangular.
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Question 1901 Mark
Write down the negation of following compound statement:
|x| is equal to either x or -x.
Answer
Let p:|x| is equal to x.
q:|x| is equal to -x.
Then, the negation of the given compound statement is:
~(p v q): |x| is not equal to JC and it is not equal to -x.
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Question 1911 Mark
Write down the converse of following statement:
If the sum of squares of two sides of a triangle is equal to the square of third side of a triangle, then the triangle is right angled.
Answer
If the triangle is right triangle, then the sum of the squares of two sides of a triangle is equal to the square of third side.
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Question 1921 Mark
Write down the negation of following compound statement:
All rational numbers are real and complex.
Answer
Let p: All rational numbers are real.
q: All rational numbers are complex.
~p: All rational numbers are not real.
~q; All rational numbers are not complex.
Then, the negation of the given compound statement is:
~(p ∧ q): All rational numbers are not real or not complex.
[~(p ∧ q) = ~p v ~ q]
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Question 1931 Mark
Determine the contrapositive of the following statements:
If it snows, then they do not drive the car.
Answer
If they do not drive the car, then there is no snow.
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Question 1941 Mark
Write down the contrapositive of the following statement:
If n is a natural number, then n is an integer.
Answer
If n is not an integer, then it is not a natural number.
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Question 1951 Mark
Check the validity of the following statements:
q: 125 is a multiple of 5 and 7.
Answer
The statement is:
"125 is multiple of 5 and 7"
Since 125 is a multiple of 5 but it is not a multiple of 7. So, q is not a true statement i.e. the statement "q" is not a valid statement.
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Question 1961 Mark
Write down the contrapositive of the following statement:
If x is a real number such that 0 < x < 1, then x 2 < 1.
Answer
If x 2 > 1 then x is not a real number such that 0 < x < 1.
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Question 1971 Mark
Write the negation of the following statements:
The sun is cold.
Answer
Negation of the given statement:
The sun is not cold.
Or
It is not true that the sun is cold.
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Question 1981 Mark
Which of the following statements are true and which are false? In each case give a valid reason for saying so:
q: The centre of a circle bisects each chord of the circle.
Answer
False. Because, a chord does not have to pass through the centre.
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Question 1991 Mark
Write down the converse of following statement:
If two triangles are similar, then the ratio of their corresponding sides are equal.
Answer
If the ratio of corresponding sides of two triangles are equal, then triangles are similar.
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Question 2001 Mark
Are the following pairs of statements are negation of each other:
The number x is not a rational number.
The number x is not an irrational number.
Answer
The given statement in this pair are the negation of each other.
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Question 2011 Mark
Identify the Quantifiers in the following statement:
There exists a triangle which is not equilateral.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 2021 Mark
State the converse and contrapositive of the following statements:
I go to a beach whenever it is a sunny day.
Answer
Converse:
If I go to a beach, then it is a sunny day.
Contrapositive:
If I do not go to a beach, then it is not a sunny day.
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Question 2031 Mark
State the converse and contrapositive of the following statements:
If a quadrilateral is a parallelogram, then its diagonals bisect each other.
Answer
Converse:
If the diagonals of a quadrilateral bisect each other, then it is a parallelogram.
Contrapositive:
If the diagonals of a quadrilateral do not bisect each other, then it is not a parallelogram.
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Question 2041 Mark
Write the negation of the following statements:
There exists $\text{x}\in\text{N},\text{x}+3=10$
Answer
The Negation of the statement:
There exists $\text{x}\in\text{N},\text{x}+3=10$
is
For every $\text{x}\in\text{N},\text{x}+3\not=10$
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Question 2051 Mark
Translate the following statement into symbolic form:
x and y are even integers.
Answer
p: x is even integers.q: y is even integers.
p ∧ q: x andy are even integers.
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Question 2061 Mark
Write down the contrapositive of the following statement:
If x = y and y = 3, then x = 3.
Answer
If x ≠ 3, then x ≠ y or y ≠ 3.
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Question 2071 Mark
Write down the negation of following compound statement:
A triangle has either 3-sides or 4-sides.
Answer
Let p: A triangle has 3-sides.
q: A triangle has 4-sides.
Then, the negation of the given compound statement is:
~(p v q): A triangle has neither 3-sides nor 4-sides.
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Question 2081 Mark
Write down the negation of following compound statement:
$x = 2$ and $x = 3$ are roots of the Quadratic equation $x^2 - 5x + 6 = 0.$
Answer
Let $p; x = 2$ is root of quadratic equation $x^2 - 5x + 6 = 0.$
$q: x = 3$ is root of quadratic equation $x^2 - 5x + 6 = 0.$
Then, the negation of the given compound statement is:
$\sim(p ∧ q): x = 2$ is not a root of quadratic equation $x^2- 5x + 6 = 0$ or $x = 3$ is not a root of the quadratic equation $x^2 – 5x + 6 = 0.$
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Question 2091 Mark
Write the component statements of the following compound statements and check whether the compound statement is true or false:
Square of an integer is positive or negative.
Answer
The component statements of the given compound statement are:
  1. Square of an integer is positive.
  2. Square of an integer is negative.
The compound statement is true because the first statement is true. Since the connective used is "or" and one of the component statements is true, the compound statement is true.
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Question 2101 Mark
State the converse and contrapositive of the following statements:
A positive integer is prime only if it has no divisors other than 1 and itself.
Answer
Converse:
If a positive integer has no divisors other than 1 and itself, then it is prime.
Contrapositive:
If a positive integer has some divisors other than 1 and itself, then it is not prime.
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Question 2111 Mark
Which of the following sentences are statements? Justify.Every set is an infinite set.
Answer
We know that is either true or false but not both simultaneously.
It is false. Hence, it is a statement.
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Question 2121 Mark
Identify the Quantifiers in the following statement:
There exists a real number which is not a rational number.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
There exists.
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Question 2131 Mark
Find out the following sentences are statements and which are not. Justify your answer.
The product of (-1) and 8 is 8.
Answer
It is an assertive sentence; therefore, it is a statement. But -1 × 8 = -8 therefore, the statement is false.
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Question 2141 Mark
Determine the contrapositive of the following statements:
If he has courage he will win.
Answer
If he does not win, then he does not have courage.
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Question 2151 Mark
Find the component statements of the following compound statements.
$\sqrt{7}$ is a rational number or an irrational number.
Answer
p: $\sqrt{7}$ is a rational number.
q: $\sqrt{7}$ is a irrational number.
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Question 2161 Mark
Find out the following sentences are statements and which are not. Justify your answer.
All real numbers are complex numbers.
Answer
It is true because we can write a real number as x + 0 i. So, it is a true statement.
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Question 2171 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Go!
Answer
It is an exclamatory sentence, so it is not a statement.
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Question 2181 Mark
Identify the Quantifiers in the following statement:
For all negative integers $x, x^3$ is also a negative integers.
Answer
Quantifier are the phrases like ‘There exists’ and ‘For every1, ‘For all’ etc.
For all.
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Question 2191 Mark
Form the biconditional statement p ↔ q, where.
p: The unit digit of an integer is zero.
q: It is divisible by 5.
Answer
p ⟷ q: The unit digit of on integer is zero, if and only if it is divisible by 5.
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Question 2201 Mark
Find out the following sentences are statements and which are not. Justify your answer.
Every set is a finite set.
Answer
It is a false assertive sentence because there are some sets that are infinite like the set of all real numbers. Therefore, it is a statement.
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