Consider the following data:
- Girls: Average marks in English = 9, Average marks in Hindi = 8
- Boys: Average marks in English = 8, Average marks in Hindi = 7
- Overall average marks: English = 8.8, Hindi = x

What is the value of x in the above table?

Correct Answer: (A) 7.8

Using the weighted average for English marks: $\frac{9G+8B}{G+B}=8.8⟹9G+8B=8.8G+8.8B⟹0.2G=0.8B⟹G=4B$$\frac{9G + 8B}{G + B}$ = 8.8 $\implies$ 9G + 8B = 8.8G + 8.8B $\implies$ 0.2G = 0.8B $\implies$ G = 4B. The ratio of girls to boys is $4 : 1$. The overall average in Hindi is $x =$$\frac{8G + 7B}{G + B}$ = $\frac{8(4) + 7(1)}{4 + 1}$ = $\frac{32 + 7}{5}$ = $\frac{39}{5}$ = 7.8.