Question

The ratio of the present ages of A and B is 5 : 6. Eight years ago, the ratio of their ages was 4 : 5. What will be the ratio of the ages of A and B after 8 years from now?

• A. 9 : 11
• B. 8 : 9
• C. 6 : 7
• D. 7 : 8

Answer 1

Answer:

C. 6 : 7

Solution:

Given:

The ratio of the present ages of A and B is 5 : 6.

Eight years ago, the ratio of their ages was 4 : 5.

Calculation:

Let present ages of A and B be 5a and 6a respectively.

8 year ago age of A was (5a - 8) years

8 years ago age of B was (6a - 8) years

Accordingly,

(5a - 8) : (6a - 8) = 4 : 5

⇒$\frac{(5a - 8)}{(6a - 8)} =\frac{4}{5}$

⇒ 25a - 40 = 24a - 32

⇒ a = 8

Present age of A and B is 40 years and 48 years respectively

∴ Required ratio = (40 + 8) : (48 + 8) = 48 : 56 = 6 : 7