Seven years ago, the ratio of the ages of A and B was 4 : 5. Eight years hence, the ratio of the ages of A and B will be 9 : 10. What is the sum of their present ages in years?

41

ATQ,

Lets assume present age of A is 4x + 7

                   present age of B is 5x + 7

Given, 8 years hence ratio of ages of A and B = \(\frac{4X + 7 + 8}{5X + 7 + 8}\) = \(\frac{9}{10}\)

⇒ 40x + 150 = 45x + 135

⇒ x = 3

Present age of A = 19

Present age of B = 22

Sum of present ages of A and B = 41 years