Acing questions on Ratio and Proportion for SI exam

By Banda Ravipal Reddy Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exam. Here are some practice questions and answers along with solutions on the Ratio and Proportion topic. 1. What is the duplicate ratio of 4: 9? A. 16 : 81 B. 64 : […]

By Banda Ravipal Reddy

Hyderabad: This article is in continuation to the last article on preparation for the Sub-Inspector of Police recruitment exam. Here are some practice questions and answers along with solutions on the Ratio and Proportion topic.

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1. What is the duplicate ratio of 4: 9?
A. 16 : 81 B. 64 : 729 C. 2 : 3 D. None of these

Ans: A

Solution:

Duplicate ratio of a: b is a2: b2.
Duplicate ratio of 4: 9 is 42: 92 = 16: 81

2. What is the sub duplicate ratio of 16: 25?

A. 4 :5 B. 256 : 625 C. 4096 : 15625 D. None of these
Ans: A

Solution:
Sub-duplicate ratio of a: b is :

Sub duplicate ratio of 16: 25= =4: 5

3. The compound ratio of 2 : 3, 5 : 4 and 8 : 9 is ?

A. 9 : 8 B. 2 : 5 C. 20 : 27 D. None of these

Ans: C

Solution:

The compound ratio of the ratios (a: b), (c: d), (e: f) is (ace: bdf)
Compound ratio of 2: 3, 5: 4 and 8: 9 = (2×5×8): (3×4×9)

= 80: 108= 20: 27
4. If 2: 3 = 12: x. Then find the value of x?

A. 12 B. 14 C. 16 D. 18
Ans: D

Solution:
a: b:: c : d a× d = b× c

2: 3 = 12: x 2× x= 3×12

X= 18
5. A sum of money is to be divided among A and B in the proportion 2: 3. If A gets Rs 3600, then find B’s share?
A. Rs 3600 B. Rs 5400 C. Rs 6400 D.Rs 6800
Ans: B

Solution:
A gets 2 units= Rs 3600

1 unit= Rs 1800

Therefore B gets 3units= 3×1800= Rs 5400

6. If a: b = 2: 3 and b: c = 5: 2. Then a: b: c =?

A. 2 : 3 : 5 :2 B. 10 : 6 : 12 C. 15 : 4 : 6 D. 10: 15: 6
Ans: D

Solution:
a: b= 2: 3= 2×5: 3×5=10:15

b: c= 5: 2= 5×3: 2×3= 15: 6
a: b: c=10: 15: 6

7. Find the fourth proportional of 3, 5 and 12?
A. 20 B. 22 C. 27 D. 33

Ans: A

Solution:

If a, b, c, d are in proportion
Then d is called the fourth proportional to a, b, c and a: b = c: d
a=3, b=5, c=12, d=?
Product of b and c= product of a and d

b×c = a×d d= =

Therefore fourth proportional of 3, 5 and 12 is 20

8. Two numbers are there in the ratio 2: 3. After subtracting 4 from both the numbers its ratio will become 5: 8. Then find initial numbers?

A. 20, 30 B.24, 36 C. 30, 45 D. None

Ans: B

Solution:

Let us assume numbers are 2x and 3x
16x-32=15x-20

X=12

Initial numbers are 2x=2×12=24and 3x=3×12=36
9. A and B together have Rs. 1210. If of A’s amount is equal to of B’s amount, how much amount does B have?

A. Rs. 460 B. Rs. 484 C. Rs. 550 D.Rs. 664

Ans: B

Solution:

Let us assume the amounts of A and B are x and y respectively.
Given that of A’s amount is equal to of B’s amount
That means
By solving i.e. x: y= 3: 2
B’s Share = = 2 × 242 = Rs 484
10. Two numbers are respectively 30% and 60% more than a third number. The ratio of the two numbers is:
A. 2: 5 B. 3: 5 C. 4: 5 D. 13 : 16

Ans: D

Solution:

Assume that 3 rd number= 100
1st number= 100 30% of 100= 100 30=130
2nd number= 100 60% of 100= 100 60= 160
Ratio of two numbers= 130:160= 13 : 16
11. A sum of money is to be distributed among A, B, C, D in the proportion of 5: 2: 4: 3. If C gets Rs. 1000 more than D, what is B’s share?
A. Rs. 500 B. Rs. 1500 C. Rs. 2000 D. None of these

Ans: C

Solution:
Given that C gets Rs. 1000 more than D

Difference in units between C and D= 4-3=1 unit

Therefore 1 unit=Rs. 1000

B’s share= 2units= 2×1000=Rs. 2000

Director, SIGMA
Sai Institute of General Mental Ability
Hyderabad

 

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