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)

No. of boys & girls be $x\&y$
$52x+42y=50(x+y)$
$2x=8y$
$x=4y\dots \dots (1)$
Total no. of students in a class $=x+y$
$=4y+y=5y$
% of boys $=\frac{4y}{5y}\times 100$
$=\frac{4}{5}\times 100=80$