Q. 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%
Explanation
(c)
Let the number of boys and girls be $x\$and$\$y
$\therefore$ $52x + 42y = 50(x + y)$
$\Rightarrow$ $2x = 8y$
$\Rightarrow$ $x = 4y$
$\therefore$ Total number of students in the class
$= x + y = 5y$
$\therefore$ Required percentage of boys
$= \frac{4y}{5y} \times 100\% = 80\%$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.