Question

The average age of three boys is $25$ years and their ages are in the ratio $3:5:7$. The age of the youngest boy is

• A. $21$ years
• B. $18$ years
• C. $15$ years
• D. $9$ years

Answer 1

The correct option is C $15$ years

Total age of $3$ boys $=(25$ $\times$ $3)$ years $=75$ years.

Ratio of their ages $=3:5:7$.
Age of the youngest $=$ $(75\times \frac{3}{15})$ years $=15$ years