SSC GD 2021 PYQ — Question 75

The correct answer is option 2 i.e. 18 years

Let Husband's age be x years and the wife's age be y years 

ATQ

$\dfrac{x + y}{2} = 20$

x + y = 40            ....(1)

After 6 years

Husband's age = (x + 6) years

Wife's age = (y + 6) years

Child = 2 years 

Average = $\dfrac{(x + 6) + (y + 6) + 2}{3}$

= $\dfrac{x + y + 14}{3}$

= $\dfrac{40 + 14}{3}$                       [using (1)]

= 18

Hence present average age of the family is 18 years.