The average age of husband, wife and their child 3 years ago was 27 years and that of wife and the child 5 years ago was 20 years. The present age of the husband is:
35 years
40 years
50 years
None of these
Explanation:
Sum of the present ages of husband, wife and child = $\left(27 \times 3 + 3 \times 3\right)$ years = 90 years.
Sum of the present ages of wife and child = $\left(20 \times 2 + 5 \times 2\right)$ years = 50 years.
$\therefore$ Husbands present age = (90 - 50) years = 40 years.