### In a class, the average score of girls in an examination is 73 and that of boys is 71. The average score for the whole class is 71.8. Find the percentage of girls :

A. 40% B. 50% C. 55% D. 60% Answer: Option A

### Solution(By Apex Team)

$\begin{array}{l}\text{Let the number of girls = x}\\ \text{And, the number of boys = y}\\ \text{According to the question,}\\ \text{73x + 71y = 71.8 (x + y)}\\ \text{1.2x = 0.8y}\\ \Rightarrow\Large\frac{x}{y}=\frac{2}{3}\\ \therefore\text{Girls}\%=\frac{2}{2+3}\times100\\ =\frac{2}{5}\times100\\ =40\%\end{array}$

A. 20
B. 21
C. 28
D. 32

A. 18
B. 20
C. 24
D. 30

A. 10 years
B. 10.5 years
C. 11 years
D. 12 years