Aptitude - Ratio and Proportion

Exercise :: Ratio and Proportion - General Questions

11. 

The salaries A, B, C are in the ratio 2 : 3 : 5. If the increments of 15%, 10% and 20% are allowed respectively in their salaries, then what will be new ratio of their salaries?

A. 3 : 3 : 10
B. 10 : 11 : 20
C. 23 : 33 : 60
D. Cannot be determined

Answer: Option C

Explanation:

Let A = 2k, B = 3k and C = 5k.

A's new salary = 115 of 2k = 115 x 2k = 23k
100 100 10

B's new salary = 110 of 3k = 110 x 3k = 33k
100 100 10

C's new salary = 120 of 5k = 120 x 5k = 6k
100 100

New ratio 23k : 33k : 6k = 23 : 33 : 60
10 10


12. 

If 40% of a number is equal to two-third of another number, what is the ratio of first number to the second number?

A. 2 : 5
B. 3 : 7
C. 5 : 3
D. 7 : 3

Answer: Option C

Explanation:

Let 40% of A = 2 B
3

Then, 40A = 2B
100 3

2A = 2B
5 3

A = 2 x 5 = 5
B 3 2 3

A : B = 5 : 3.


13. 

The fourth proportional to 5, 8, 15 is:

A. 18
B. 24
C. 19
D. 20

Answer: Option B

Explanation:

Let the fourth proportional to 5, 8, 15 be x.

Then, 5 : 8 : 15 : x

5x = (8 x 15)

x = (8 x 15) = 24.
5


14. 

Two number are in the ratio 3 : 5. If 9 is subtracted from each, the new numbers are in the ratio 12 : 23. The smaller number is:

A. 27
B. 33
C. 49
D. 55

Answer: Option B

Explanation:

Let the numbers be 3x and 5x.

Then, 3x - 9 = 12
5x - 9 23

23(3x - 9) = 12(5x - 9)

9x = 99

x = 11.

The smaller number = (3 x 11) = 33.


15. 

In a bag, there are coins of 25 p, 10 p and 5 p in the ratio of 1 : 2 : 3. If there is Rs. 30 in all, how many 5 p coins are there?

A. 50
B. 100
C. 150
D. 200

Answer: Option C

Explanation:

Let the number of 25 p, 10 p and 5 p coins be x, 2x, 3x respectively.

Then, sum of their values = Rs. 25x + 10 x 2x + 5 x 3x = Rs. 60x
100 100 100 100

60x = 30     x = 30 x 100 = 50.
100 60

Hence, the number of 5 p coins = (3 x 50) = 150.


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