Question

The no. Of boys and girls are in the ratio 7:5. The no. Of boys is8more than the no. Of girls. What is the total class strength.

Answer 1

let's assume X=boys ,y=girls
X:Y=7:5
X=8+Y
8+Y÷Y=7÷5
cross multiplication
40+5Y=7Y
40=2Y
Y=20(girls)
X=28(boys)

Answer 2

let the number of girls be 5x
number of boys is equal to 7x
according to the question
5 x + 8 is equal to 7 x
7 x- 5 x is equal to 8
2 x is equal to 8
x is equal to 8 / 2
x is equal to 4.
number of girls 5 * 4 is equal to 20.
number of boys is equal to 7*4 is equal to 28
hence the total strength of the class is 20 + 28 is equal to 48