Question

The average marks of boys in a class is $52$ and that of girls is $42$. The average marks of boys and girls combined is $50$. The percentage of boys in the class is

• A. $40$
• B. $20$
• C. $80$
• D. $60$

Answer 1

Answer: (C)

$52x + 42y = 50 (x + y)$
$2x=8y$
$\Rightarrow \frac{x}{y}=\frac{4}{1}$ and $\frac{x}{x+y}=\frac{4}{5}$
$\therefore \% of boys = 80.$