The sum of the present ages of a father and his son is 60 years. Six years ago, fathers age was five times the age of the son. After 6 years, sons age will be:

12 years

14 years

18 years

20 years

Explanation:

Let the present ages of son and father be $ x $ and $\left(60 -x\right)$ years respectively.

Then,$\left (60 - x\right)$ - 6 = 5$\left(x- 6\right)$

$\Rightarrow$ 54 - $ x $ = 5$ x $ - 30

$\Rightarrow$ 6$ x $ = 84

$\Rightarrow x $ = 14.

$\therefore$ Sons age after 6 years = $\left(x+ 6\right)$ = 20 years..