Questions · Page 4 of 4

M.C.Q. [1 Marks Each]

MCQ 1511 Mark
If $\frac{2}{3}$ of a number if $20$ less than the original number, then the number is:
  • A
    $40$
  • B
    $120$
  • $60$
  • D
    $80$
Answer
Correct option: C.
$60$

 Let the original number be $x.$
According to the question we can write as $\Big(\frac{2}{3}\Big)\text{x}+\text{20x}$
On rearranging $\text{x}-\Big(\frac{2}{3}\Big)\text{x}=20$
Now taking the $L.C.M$ od $1$ and $3$ is $3$
$\frac{(\text{3x - 2x})}{ 3=20}$
$\frac{\text{x}}{3=20}$
Again by transposing $x = 60$
So the original number is $60$

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MCQ 1521 Mark
Mark $(\checkmark)$ against the correct answer: $3 + 23x - 8x^2 =\  ?$
  • A
    $(1 - 8x)(3 + x)$
  • $(1 + 8x)(3 - x)$
  • C
    $(1 - 8x)(3 - x)$
  • D
    None of these
Answer
Correct option: B.
$(1 + 8x)(3 - x)$

Solution: 
$(1 + 8x)(3 - x)$
$3 + 23x - 8x^2$
$= 3 + 24x - x - 8x^2$
$= 3(1 + 8x)-x(1 + 8x)$
$= (1 + 8x)(3 - x)$
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MCQ 1531 Mark
The sum of three consecutive multiples of $7$ is $357.$ Find the smallest multiple.
  • $112$
  • B
    $126$
  • C
    $119$
  • D
    $116$
Answer
Correct option: A.
$112$
$112$
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MCQ 1541 Mark
If the sum of two consecutive numbers is $71$ and one number is $x,$ then the other number is:
  • $x + (x + 1) = 71$
  • B
    $x + (x + 2) = 71$
  • C
    $x + x = 71 $
  • D
    None of these.
Answer
Correct option: A.
$x + (x + 1) = 71$

 If $x$ is one number, then $x + 1$ would be the next consecutive number. Since the sum of the two consecutive numbers is $71,$ we can say,
$x + (x + 1) = 71$
$2x + 1 = 71$
$2x = 70$
$x = 35,$ so $x + 1 = 36$
$35 + 36 = 71$

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MCQ 1551 Mark
The perimeter of a rectangle is $40\ cm.$ If its width is $10\ cm,$ then find the length.
  • A
    $40$
  • $10$
  • C
    $30$
  • D
    $20$
Answer
Correct option: B.
$10$

 Perimeter of a rectangle $= 40\ cm$
Width $= 10\ cm$
Let the length be $x.$
Perimeter of rectangle $= 2($length $+$ width$)$
$40 = 2(x + 10)$
$\frac{40}{2} = \text{x} + 10$
$20 = x + 10$
$x = 20 - 10 = 10$
Thus, the length is also $10\ cm.$
Hence, we can say, that the given rectangle is basically a square, with all its sides equal.

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MCQ 1561 Mark
The root of the equation $\frac{\text{5x}}{3}= 30$ is:
  • A
    $9$
  • B
    $12$
  • C
    $15$
  • $18$
Answer
Correct option: D.
$18$

 $\frac{\text{5x}}{3}= 30$
$\Rightarrow \text{5x}= 3 \times 30 = 90$
$ \Rightarrow \text{x}= \frac{90}{5}=18$

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MCQ 1571 Mark
The sum of two digit number and the number formed by interchanging its digit is $110.$ If ten is subtracted from the first number, the new number is $4$ more than $5$ times of the sum of the digits in the first number. Find the first number.
  • A
    $46$
  • B
    $48$
  • $64$
  • D
    $84$
Answer
Correct option: C.
$64$
$64$
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MCQ 1581 Mark
When a number is added to itself, it becomes $24.$ What is the number$?$
  • $12$
  • B
    $21$
  • C
    $2$
  • D
    $4$
Answer
Correct option: A.
$12$

 Let the number be $x.$
$x + x = 24$
$2x = 24$
$\text{x} = \frac{24}{2}$
$x = 12$

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MCQ 1591 Mark
The root of the equation $3x + 8 = 14$ is:
  • A
    $1$
  • $2$ 
  • C
    $-1$
  • D
    $\frac{1}{2}$
Answer
Correct option: B.
$2$ 

 $3\text{x} + 8 = 14$
$\Rightarrow 3\text{x} = 14 - 8 = 6$
$\Rightarrow\text{x}= \frac{6}{3}= 2$

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MCQ 1601 Mark
What is the length of the rectangle whose breadth is $10\ cm$ and perimeter $60\ cm$
  • A
    $15\ cm$
  • B
    $16\ cm$
  • $20\ cm$
  • D
    $25\ cm$
Answer
Correct option: C.
$20\ cm$
 Breadth of the rectangle $= 10\ cm.$  And Perimeter of the rectangle $= 60\ cm$
Given
We know that,
Perimeter of rectangle $= 2(l+b)$
Substituting the values in the above formula, we get,
$\Rightarrow 60\ cm = 2(l + 10)\ cm$
$\Rightarrow 60\ cm = 2l + 20\ cm$
$\Rightarrow 60 - 20cm = 2l$
$\Rightarrow 40\ cm = 2l$
$\Rightarrow\frac{40}{2}\text{cm} = \text{l}$
$\Rightarrow l = 20\ cm$
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MCQ 1611 Mark
By selling a bicycle for $Rs.1885,$ a man gains $16\%.$ At what price did he buy the bicycle$?$
  • $Rs. 1625$
  • B
    $Rs. 1825$
  • C
    $Rs. 2000$
  • D
    None.
Answer
Correct option: A.
$Rs. 1625$

Let $CP = x$
$\text{Gain}=\frac{16}{100}\text{x}=\frac{\text{4x}}{25}$
$\text{CP}=\frac{\text{4x}}{25}+\text{x}=\frac{\text{29x}}{25}$
$\frac{\text{29x}}{25}=1885$
$\text{x}=\text{Rs. 1625}$

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MCQ 1621 Mark
Find the solution of the following equation: $\text{m}-\frac{\text{m}-1}{3}=1-\frac{\text{m}-2}{2}$
  • $\frac{10}{7}$
  • B
    $-\frac{10}{7}$
  • C
    $\frac{5}{7}$
  • D
    $-\frac{5}{7}$
Answer
Correct option: A.
$\frac{10}{7}$

 Taking, $\text{m}-\frac{\text{m}-1}{3}=1-\frac{\text{m}-2}{2}$
$\Rightarrow\frac{\text{m}-\text{m}+1}{3}=\frac{2-\text{m}+2}{2}$
$\Rightarrow\frac{\text{2m}+1}{3}=\frac{4-\text{m}}{2}$
$\Rightarrow2{\text({2\text{m}}+1})=3(4-\text{m})$
$\Rightarrow{\text{4m}+2}=12-\text{3m}$
$\Rightarrow{\text{4m}+2}\text{3m}=12-2$
 $\Rightarrow\text{7m}=10$
$\Rightarrow\text{m}=\frac{10}{7}$

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MCQ 1631 Mark
The root of the equation $2y = 5 (7 - y )$ is:
  • $5$
  • B
    $-5$
  • C
    $3$
  • D
    $-3$
Answer
Correct option: A.
$5$

 $2\text{y} = 5(\text{7} - \text{y})$
$\Rightarrow2\text{y} = 35 - 5\text{y} $
$\Rightarrow2\text{y} + 5\text{y}= 35$
$\Rightarrow\text{7y = 35 }\Rightarrow\text{y}= - \frac{35}{7}= 5$

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MCQ 1641 Mark
The sum of three consecutive integers is $180.$ Find these integers.
  • A
    $58, 59, 60$
  • B
    $60, 61, 62$
  • $59, 60, 61$
  • D
    $60, 60, 60$
Answer
Correct option: C.
$59, 60, 61$

 Let $'a' a + 1,$ and $a + 2$ are the three consecutive integers.
According to the question,
$a + a + 1 + a + 2 = 180$
$\Rightarrow 3a + 3 = 180$
$\Rightarrow a + 1 = 160$
$\Rightarrow a = 60 - 1$
$\Rightarrow a = 59$
Therefore, the required integers are $59, 60$ and $61.$

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MCQ 1651 Mark
The root of the equation $3y + 4 = 5y - 4$ is:
  • A
    $1$
  • B
    $2$
  • C
    $3$
  • $4$
Answer
Correct option: D.
$4$

 $3\text{y} + 4 = 5\text{y} - 4$
$\Rightarrow5\text{y} - 3\text{y} = 4 + 4$
$\Rightarrow\text{2y}=8 \Rightarrow\frac{8}{2}=4$

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MCQ 1661 Mark
If $\frac{\text{z}}{\text{(z + 15)}} = \frac{4}{9} $ then the value of $‘z’$ is:
  • A
    $11$
  • $12$
  • C
    $13$
  • D
    $14$
Answer
Correct option: B.
$12$
 $\frac{\text{z}}{\text{(z + 15)}} = \frac{4}{9} $
Cross multiplication
$9z = 4(z + 15)$
$9z = 4z + 60$
$5z = 60$
$\text{z}=\frac{60}{5}$
$z = 12$
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MCQ 1671 Mark
A number when subtracted from $40$ results into $15$. This statement in the form of an equation is:
  • $40 - x = 15$
  • B
    $x - 40 = 15$
  • C
    $40 + x = 15$
  • D
    $40x = 15$
Answer
Correct option: A.
$40 - x = 15$

Let the number be $x.$

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MCQ 1681 Mark
The root of the equation $2y = 5(3 + y)$ is:
  • A
    $\text{5}$
  • B
    $\frac{1}{5}$
  • $-\text{5}$
  • D
    $-\frac{1}{5}$
Answer
Correct option: C.
$-\text{5}$
$2\text{y} = 5 (3 + \text{y})$
$\Rightarrow2\text{y} = 15 + 5\text{y}$
$\Rightarrow5\text{y} – 2\text{y} = -15$
$\Rightarrow\text{3y} = - 15$
$\Rightarrow\text{y}= - \frac{15}{3}= - 5$
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MCQ 1691 Mark
How old will I be after $10$ years, if my age before $10$ years was $‘x’$ years$?$
  • $x + 20$
  • B
    $x - 20$
  • C
    $x + 10$
  • D
    $x ‐ 10$
Answer
Correct option: A.
$x + 20$

Before $10$ Years $x$
Today after $10$ Years $- x + 10$
After $10$ Years $x + 10 + 10 = x + 20$

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MCQ 1701 Mark
What is the degree of the equation $x^2 + 2x - 3 = x^2 + 7x - 23.$
  • A
    Zero
  • B
    One
  • Two
  • D
    Three
Answer
Correct option: C.
Two
C.  Two
Solution:
The degree of the equation is defined as the highest power of variables present in an equation, so answer is two.
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MCQ 1711 Mark
The root of the equation $7(x - 1) = 21$ is:
  • A
    $1$
  • B
    $2$
  • C
    $3$
  • $4$
Answer
Correct option: D.
$4$
$\text{(x} -1 ) =21 \Rightarrow \text{x} - 1= \frac{21}{7}=3$
$ \Rightarrow \text{x = 4.}$
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MCQ 1721 Mark
The present age of Sahil’s mother is three times the present age of Sahil. After $5$ years their ages will add to $66$ years. Find their present ages.
  • A
    $28$ years, $42$ years
  • B
    $14$ years, $56$ years 
  • C
    $28$ years, $56$ years
  • $14$ years, $42$ years
Answer
Correct option: D.
$14$ years, $42$ years
$14$ years, $42$ years
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MCQ 1731 Mark
If $x$ is an even number, then the next even number is:
  • A
    $x + 3$
  • B
    $x + 4$
  • C
    $x + 1$
  • $x + 2$
Answer
Correct option: D.
$x + 2$
If $x = 2,$ then $x + 2 = 2 + 2 = 4.$
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MCQ 1741 Mark
The root of the equation $3x + 4 = 13$ is:
  • A
    $1$
  • B
    $2$
  • $3$
  • D
    $4$
Answer
Correct option: C.
$3$

 $3\text{x} + 4 = 13$
$\Rightarrow3\text{x}= 13 – 4 = 9$
$ \Rightarrow \text{x}= \frac{9}{3}=3$

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MCQ 1751 Mark
Three consecutive integers add up to $51.$ The integers are:
  • A
    $17, 18, 19$
  • B
    $18, 19, 20$
  • $16, 17, 18$
  • D
    $15, 16, 17$
Answer
Correct option: C.
$16, 17, 18$
Let the three consecutive integers be $x, x + 1, x + 2$
$x + (x + 1) + (x + 2) = 51$
$3x + 3 = 51$
$3x = 51 - 3$
$\text{x} = \frac{48}{3} = 16$
$x + 1 = 16 + 1 = 17$
$x + 2 = x + 2 = 18$
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MCQ 1761 Mark
If a number increased by $8\%$ of itself gives $135,$ then that number is:
  • $125$
  • B
    $112$
  • C
    $100$
  • D
    None
Answer
Correct option: A.
$125$

Given, a number increased by $8\%$ of itself gives $135.$
Thus, $x + 8\%$ of $x = 135$
$\Rightarrow\frac{\text{108x}}{100}=135$
$\Rightarrow\text{x}=135\times\frac{100}{108}=125$
Thus, the number is $125.$

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MCQ 1771 Mark
A number is $56$ greater than the average of its third, quarter and one-twelfth. Find the number.
  • A
    $85$
  • B
    $64$
  • $72$
  • D
    $40$
Answer
Correct option: C.
$72$
$72$
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MCQ 1781 Mark
Tick $(\checkmark)$ the correct answer: If $\frac{\text{n}}{\text{n}+15}=\frac{4}{9},$ then $​​\text{n}=?$
  • A
    $4$
  • B
    $6$
  • C
    $9$
  • $12$
Answer
Correct option: D.
$12$
$\frac{\text{n}}{\text{n}+15}=\frac{4}{9}$
$\Rightarrow\text{9n}=4(\text{n}+15)$
$\Rightarrow9\text{n}=4\text{n}+60$
$\Rightarrow9\text{n}-4\text{n}=60$
$\Rightarrow5\text{n}=60$
$\Rightarrow\text{n}=\frac{60}{5}=12$
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MCQ 1791 Mark
If $15$ is subtracted from a number, it becomes $-5.$ This statement in the form of an equation is:
  • A
    $x + 15 = -5$
  • B
    $x - 15 = 5$
  • C
    $x + 15 = 5$
  • $x - 15 = -5$
Answer
Correct option: D.
$x - 15 = -5$

Let the number be $x.$

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MCQ 1801 Mark
A number consists of two digits whose sum is $8.$ If $18$ is added to the number, its digits are interchanged. Find the number:
  • $35$
  • B
    $63$
  • C
    $53$
  • D
    $92$
Answer
Correct option: A.
$35$

The number is $10x + y$
When digits are reversed, the number becomes $10y + x.$
We have,
$x + y = 8 (i)$
$10x + y + 18 = 10y + x$
$x - y + 2 = 0 (ii)$
Solving $(i)$ and $(ii),$ we get
$x = 3, y = 5$
$\therefore$ The number is $35.$

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MCQ 1821 Mark
Write in equation: Adding $4$ times $x$ to $16$ is $45:$
  • $4x + 16 = 45$
  • B
    $16x + 4 = 45$
  • C
    $4 × 16 + x = 45$
  • D
    $16 × 45 = 4x$
Answer
Correct option: A.
$4x + 16 = 45$

Adding $4$ times $x$ to $16$ is $45$ is $4x\ 16 = 45.$

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MCQ 1831 Mark
Tick $(\checkmark)$ the correct answer: If $5t - 3 = 3t - 5,$ then $t = ?$
  • A
    $1$
  • $-1$
  • C
    $2$
  • D
    $-2$
Answer
Correct option: B.
$-1$

$5\text{t}-3=3\text{t}-5$
$\Rightarrow5\text{t}-3\text{t}=3-5$
$\Rightarrow2\text{t}=-2$
$\Rightarrow\text{t}=\frac{-2}{2}=-1$

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MCQ 1841 Mark
Tick $(\checkmark)$ the correct answer: The ages of $A$ and $B$ are in the ratio $5 : 7.$ Four years from now the ratio of their ages will be $3 : 4.$ The present age of $B$ is:
  • A
    $20$ years
  • $28$ years
  • C
    $15$ years
  • D
    $21$ years
Answer
Correct option: B.
$28$ years

 Let the number be $x.$
Let $x$ be the common multiple of the ages of A$$ and $B$.Then. the ages of $A$ and $B$ would be $5x$ and $7x,$ respectively.  
$\therefore\frac{5\text{x}+4}{7\text{x}-4}=\frac{3}{4}$
$\Rightarrow4( 5\text{x} +4 ) = 3 ( 7\text{x} + 4 )$
$\Rightarrow20\text{x} + 16 = 21\text{x} + 12$
$\Rightarrow16 - 12 = 21\text{x} - 20\text{x}$
$\Rightarrow4 = \text{x}$
$\Rightarrow\text{x} = 4 $
$\therefore$ Age of $\text{B} = 7(\text{x}) = 7\times4 $
$= 28 \text{ years}$

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MCQ 1851 Mark
The difference of two numbers is $21.$ The larger number is $x.$ The smaller number is:
  • A
    $21 + x$
  • B
    $21 - x$
  • $x - 21$
  • D
    $-x - 21$
Answer
Correct option: C.
$x - 21$

$ x -$ smaller number $= 21$
$\Rightarrow $ smaller number $= x - 21$

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MCQ 1861 Mark
Solve $2y + 9 = 4.$
  • $\frac{-5}{2}$
  • B
    $\frac{1}{2}$
  • C
    $2$
  • D
    None of these
Answer
Correct option: A.
$\frac{-5}{2}$
$\frac{-5}{2}$
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MCQ 1871 Mark
The value of $x$ in $-\frac{2}{3}=\text{2x}$ is $3:$
  • A
    $\frac{1}{3}$
  • $-\frac{1}{3}$
  • C
    $3$
  • D
    $-3$
Answer
Correct option: B.
$-\frac{1}{3}$

 $-\frac{1}{3}= \text{2x}\Rightarrow \text{x}= - \frac{1}{3}$

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MCQ 1881 Mark
Seven times a number is $42.$ This statement in the from of an equation is:
  • A
    $x + 7 = 42$
  • $7x = 42$
  • C
    $\frac{\text{x}}{7}=42$
  • D
    $x - 7 = 42$
Answer
Correct option: B.
$7x = 42$

 Let the number be $x.$

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MCQ 1891 Mark
What is the value of $x$ if $x + 9 = 12?$
  • A
    $8$
  • B
    $6$
  • C
    $2$
  • $3$
Answer
Correct option: D.
$3$
$ x + 9 = 12$
$x = 12 - 9$
$x = 3$
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MCQ 1901 Mark
The perimeter of the rectangle is 20cm. If the length of the rectangle is $6\ cm,$ then its breadth will be:
  • A
    $10\ cm$
  • B
    $14\ cm$
  • $4\ cm$
  • D
    $6\ cm$
Answer
Correct option: C.
$4\ cm$

 Perimeter of rectangle $= 2($Length $+$ Breadth$)$
$20 = 2(6 + x)$
$6 + x =\frac{20}{2}$
$6 + x = 10$
$x = 10 - 6$
$x = 4\ cm$

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MCQ 1911 Mark
Variables and numbers can be shifted from one side of an equation to other by:
  • Transposition
  • B
    Distributivity
  • C
    Commutativity
  • D
    Associativity
Answer
Correct option: A.
Transposition
Changing position of numbers and variables is called transposing.
In linear equation, the shifting of a number from one side of an equation to other is called transposition.
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M.C.Q. [1 Marks Each] - Page 4 - MATHS STD 8 Questions - Vidyadip