Question

The no of boys and girls in a class of ratio7:5.The no of boys is 8more than the no of girls .What is the total class strength.

Answer 1

let the no of boys and girls be 7x and 5x
also
7x = 5x + 8
2x=8
x=4
therefore 7x=28
5x=20

Answer 2

given $\frac{b}{g} = \frac{7}{5}$
>5b-7g=0-----------(1)
also given that
b=g+8 substitute in (1)
>5(g+8)-7g=0
>5g+40-7g=0
>2g=40
>no.of girls(g)=20-----------(2)
substitute in(1) we get
5b=7×20
no. of boys(b)=7×4=28---------(3)
from(2)&(3)
total strength=g+b=20+28=48.
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