1 Mark Question

Question 11 Mark

Write the following sets using listing method and classify into finite or infinite set :

F = {(a, b) | a, b ∈ Q, a + b = 11}

Answer

F = {(a, b ) | a, b Î Q, a +b = 11 }
F = {(6, 5), (3, 8), (3.5,7.5), (-15, 26),. . .} infinitely many such pairs can be written.
so, F is an infinite set.

View full question & answer→

Question 21 Mark

Write the following sets using listing method and classify into finite or infinite set :
$E=\left\{x \mid x \in I, x^2=100\right\}$

Answer

$
\begin{aligned}
& \mathrm{E}=\left\{x \mid x \in \mathrm{I}, x^2=100\right\} \\
& \mathrm{E}=\{-10,10\} . \quad \therefore \mathrm{E} \text { is a finite set }
\end{aligned}
$

View full question & answer→

Question 31 Mark

Write the following sets using listing method and classify into finite or infinite set :

D = {(a, b) | a, b ∈ W, a + b = 9}

Answer

$\mathrm{D}=\{(a, b) \mid a, b \in \mathrm{W}, a+b=9\}$
We have to find the pairs of $a$ and $\mathrm{b}$ such that, $a$ and $b$ are whole numbers and $a+b=9$.
Let us first write the value of $a$ and then the value of $b$. By keeping this order set $\mathrm{D}$ can be written as
$
\mathrm{D}=\{(0,9),(1,8),(2,7),(3,6),(4,5),(5,4),(6,3),(7,2),(8,1),(9,0)\} \text {, }
$
In this set, the number of pairs is finite and could be counted
$\therefore$ Set $\mathrm{D}$ is a finite set.

View full question & answer→

Question 41 Mark

Write the following sets using listing method and classify into finite or infinite set :

C = {x | x ∈ N, and x is divisible by 7 }

Answer

$
\begin{aligned}
& \mathrm{C}=\{x \mid x \in \mathrm{N} \text { and } x \text { is divisible by } 7 .\} \\
& \mathrm{C}=\{7,14,21, \ldots\} \text { This is an infinite set. } \\
\end{aligned}
$

View full question & answer→

Question 51 Mark

Write the following sets using listing method and classify into finite or infinite set :

B = {x | x ∈ N and 3x -1 = 0}

Answer

$
\begin{aligned}
& \mathrm{B}=\{x \mid x \in \mathrm{N} \text { and } 3 x-1=0\} \\
& 3 x-1=0 \quad \therefore 3 x=1 \quad x=\frac{1}{3} \\
& \text { But } \frac{1}{3} \notin \mathrm{N} \quad \therefore \mathrm{B}=\{\quad \therefore \mathrm{B} \text { is finite set. }\\
\end{aligned}
$

View full question & answer→

Question 61 Mark

Write the following sets using listing method and classify into finite or infinite set :

A = {x | x ∈ N and x is an odd number}

Answer

A = {x | x ∈ N and x is an odd number.}
A = {1, 3, 5, 7, ......} This is an infinite set.

View full question & answer→

Question 71 Mark

Let the set of English alphabets be the Universal set. The letters of the word ‘LAUGH’ is one set and the letter of the word ‘CRY’ is another set. Can we say that these are two disjoint sets? Observe that intersection of these two sets is empty.

Answer

Let A = {L, A, U, G, H}
B = {C, R, Y}
Now, A ∩ B = φ
∴ A and B are disjoint sets.

View full question & answer→

Question 81 Mark

Observe the set A, B, C given by Venn diagrams and write which of these are disjoint sets.

Answer

Here, A = {1, 2, 3, 4, 5, 6, 7}
B = {3, 6, 8, 9, 10, 11, 12}
C = {10, 11, 12}
Now, A ∩ C = φ
∴ A and C are disjoint sets.

View full question & answer→

Question 91 Mark

Write with reasons, which of the following sets are finite or infinite : Set of rational number

Answer

Set of rational number
The number of elements in the set of rational numbers are unlimited and uncountable.
∴ Given set is an infinite set.

View full question & answer→

Question 101 Mark

Write with reasons, which of the following sets are finite or infinite : Set of whole numbers

Answer

Set of whole numbers
The number of elements in the set of whole numbers are unlimited and uncountable.
∴ Given set is an infinite set.

View full question & answer→

Question 111 Mark

Write with reasons, which of the following sets are finite or infinite : Set of apparatus in laboratory

Answer

Set of apparatus in laboratory
The number of apparatus in the laboratory are limited and can be counted.
∴ Given set is a finite set.

View full question & answer→

Question 121 Mark

Write with reasons, which of the following sets are finite or infinite : Set of people from your village.

Answer

Set of people from your village.
The number of people in a village is limited and can be counted.
∴ Given set is a finite set.

View full question & answer→

Question 131 Mark

Write with reasons, which of the following sets are finite or infinite : C = Set of students of class 9 from your school.

Answer

C = Set of students of class 9 from your school.
The number of students in a class is limited and can be counted.
∴ C is a finite set.

View full question & answer→

Question 141 Mark

Write with reasons, which of the following sets are finite or infinite : B = {y | y < -1, y is an integer}

Answer

B = (y | y < -1, y is an integer}
∴ B = { …,-4, -3, -2}
The number of elements in B are unlimited and uncountable.
∴ B is an infinite set.

View full question & answer→

Question 151 Mark

Write with reasons, which of the following sets are finite or infinite : A = {x | x<10, xisa natural number}

Answer

A={x| x < 10, x is a natural number}
∴ A = {1,2, 3,4, 5,6, 7, 8, 9}
The number of elements in A are limited and can be counted.
∴A is a finite set.

View full question & answer→

Question 161 Mark

If A = {1, 2, 3} and B = {1, 2, 3, 4}, then A ≠ B verify it

Answer

Here, 4 ∈ B but 4 ∉ A
∴ A and B are not equal sets,
i.e. A ≠ B

View full question & answer→

Maths 1 Mark Question

Take a timed test