ML Aggarwal Solution Class 10 Chapter 7 Ratio and Proportion MCQs

 MCQs

Question 1

The ratio of 45 minutes to $5 \frac{3}{4}$  hours is

(a) 180:23

(b) 3:23

(c) 23:3

(d) 6:23

Solution:

ratio of 45 minutes to $5 \frac{3}{4}$ hours is

45 minutes to : $5 \frac{3}{4}$ hours

$=45: 5 \frac{3}{4} \times 60$

$=45: \frac{23}{4} \times 60$

$=45: 345$

=3: 23

Ans (b)

Question 2

The ratio of 4 litres to 900 mL is

(a) 4 : 9

(b) 40 : 9

(c) 9 : 40

(d) 20 : 9

Sol :

4l : 900 ml

= 4000 ml : 900 ml

= 4000 : 900

= 40 : 9 (b)

Question 3

When the number 210 is increased in the ratio 5 : 7, the the new number is

(a) 150

(b) 180

(c) 294

(d) 420

Sol :

210 is increased in the ratio 5 : 7, then

New increased number will be

$=210 \times \frac{7}{5}$

=294

Ans (c)

Question 4

Two numbers are in the ratio 7 : 9. If the sum of the numbers is 288, then the smaller number is

(a) 126

(b) 162

(c) 112

(d) 144

Sol :

Ratio in two number = 7 : 9

Sum of numbers = 288

Sum of ratios = 7 + 9

= 16

Smaller number $=\frac{288 \times 7}{16}$

= 126 

Ans (a)

Question 5

A ratio equivalent to the ratio $\frac{2}{3}: \frac{5}{7}$ is

(a) 4:6

(b) 5:7

(c) 15:14

(d) 14:15

Sol :

$\frac{2}{3}: \frac{5}{7}$

Multiply and divide $\frac{2}{3}$ by 7 and 

Multiply and divide $\frac{5}{7}$ by 3

$\therefore \frac{2}{3} \times \frac{7}{7}: \frac{5}{7} \times \frac{3}{3}$

$\Rightarrow \frac{14}{21}: \frac{15}{21} \Rightarrow 14: 15$

$\therefore \frac{2}{3}: \frac{5}{7}$ is equivalent 14: 15

Ans (d)

Question 6

The ratio of number of edges of a cube to the number of its faces is

(a) 2 : 1

(b) 1 : 2

(c) 3 : 8

(d) 8 : 3

Sol :

No. of edges of the cube = 12

No. of faces = 6

Ratio in edges a cube to the number of faces = 12 : 6

= 2 : 1

Ans  (a)

Question 7

If x, 12, 8 and 32 are in proportion, then the value of x is

(a) 6

(b) 4

(c) 3

(d) 2

Sol :

x, 12, 8, 32 are in proportion, then

x × 32 = 12 × 8 (∵ ad = bc)

$\Rightarrow x=\frac{12 \times 8}{32}=3$

x = 3

Ans (c)

Question 8

The fourth proportional to 3, 4, 5 is

(a) 6

(b) $\frac{20}{3}$

(c) $\frac{15}{4}$

(d) $\frac{12}{5}$

Sol :

The fourth proportion to 3, 4, 5 will be

$=\frac{4 \times 5}{3}$

$=\frac{20}{3}$

Ans (b)

Question 9

The third proportional to $6 \frac{1}{4}$ and 5 is

(a) 4

(b) $8 \frac{1}{2}$

(c) 3

(d) none of these

Sol :

The third proportional to $6 \frac{1}{4}$ and 5 is 

$\Rightarrow 6 \frac{1}{4}: 5: 5: x$

$\Rightarrow \frac{25}{4}: 5: 5: x$

$\Rightarrow x=\frac{5 \times 5}{25} \times 4$

$\Rightarrow 4(a)$

Question 10

The mean proportional between $\frac{1}{2}$ and 128 is 

(a) 64

(b) 32

(c) 16

(d) 8

Sol :

The mean proportional between $\frac{1}{2}$ and 128 is 

$=\sqrt{\frac{1}{2} \times 128}$

$=\sqrt{64}$

=8

Ans (d)