8 years ago, the ratio of ages of A and B was 9:10. The ratio of their ages 4 years from now will be 12:13. What is the age of ( in years ) of C now, if his age is 10 years more than that of A?

54

Ratio of age of A and B, 8 years ago was = 9 : 10

after 4 years from present = 12 : 13

ATQ,

\(\frac{9R + 12}{10R +12}\) = \(\frac{12}{13}\)

⇒ 117R + 156 = 120R + 144

⇒ 3R = 12

⇒ 1R = 4

Present age of A = (9 × 4) + 8 = 36 + 8 = 44

Age of C = Age of A + 10 years = 44 + 10 = 54