6 years ago , the ratio of the ages of Kunal and Sagar was 6 : 5. Four years hence, the ratio of their ages will be 11 : 10. What is Sagar's age at present ?

A. 16 years

B. 18 years

C. 20 years

D. Cannot be determined

E. None of these

Answer: Option A

Solution(By Examveda Team)

Let the ages of Kunal and Sagar 6 years ago be 6x and 5x years
Then,
$$\eqalign{ & \frac{{\left( {6x + 6} \right) + 4}}{{\left( {5x + 6} \right) + 4}} = \frac{{11}}{{10}} \cr & \Rightarrow \frac{{6x + 10}}{{5x + 10}} = \frac{{11}}{{10}} \cr & \Rightarrow 10\left( {6x + 10} \right) = 11\left( {5x + 10} \right) \cr & \Rightarrow 60x + 100 = 55x + 100 \cr & \Rightarrow 5x = 10 \cr & \Rightarrow x = 2 \cr} $$
Sagar's present age
= (5x + 6) years
= (5 × 2 + 6) years
= 16 years