Question

The number of boys and girls in a class are in ratio $7:5$. The number of boys is $8$ more than the number of girls. What is the total class strength?

Answer 1

Let the common ratio between number of boys and girls be $x$
Number of boys $=7x$
Number of girls $=5x$
As per the question,
Number of boys $=$ Number of girls $+8$
$7x=5x+8$
Transpose $5x$ to LHS, we will get
$7x-5x=8$

$2x=8$
Divide both sides by $2$
$x=4$
No. of boys $=7x=7\times 4=28$
No. of girls $=5x=5\times 4=20$
Total class students $28+20=48$