Six years ago the ratio of the ages of Preeti and Ruchi was 6: 5. After four years the ratio of their ages will be 11: 10. What is Ruchi's present age?

16 yr

As we are going from 6 years ago to after 4 years. That means we need to add 10.

\(\frac{6x + 10 }{5x + 10 }\) = \(\frac{11}{10}\)

(6x + 10)10 = (5x + 10)11

60x + 100 = 55x + 110

5x = 10

x = 2

Ruchi's present age is 6x + 4 = 6(2) + 4 = 16 years