Question

The average age of the students of a class is 15.8 years. The average age of boys in the class is 16.4 years and that of the girls is 15.4 years.
What is the ratio of the number of girls to the number of boys in the class?

• A. 2:1
• B. 5:2
• C. 2:5
• D. 2:3
• E. 3:2

Answer 1

The correct option is E

3:2

Let the ratio of boys to girls be k:1.

Then, $(K\times 16.4)+(1\times 15.4)=(k+1)\times 15.8\Rightarrow (16.4–15.8)k=(15.8–15.4)\Rightarrow k=\frac{2}{3}$

The ratio of boys to girls,
$=(K:1)=2:3$

Hence, ratio of girls to boys = 3:2