Question

The average age of $14$ girls in a class is $20$ years and of $18$ boys is $23$ years. Find average age of class.

• A. $21\frac{11}{16}$ years
• B. $21\frac{9}{16}$ years
• C. $21\frac{7}{16}$ years
• D. $21\frac{13}{16}$ years

Answer 1

The correct option is A $21\frac{11}{16}$ years

Given that,
Average age of $14$ girls =$20$ years
Average age of $18$ boys = $23$ years
Using the concept of weighted average,
Average age of the class = $\frac{14\times 20+18\times 23}{14+18}$
= $21\frac{22}{32}=21\frac{11}{16}$ years