Question

the number of boys and gitls in a class are in the ratio 7:5.the number of boys is 8 more than the number of girsl .what the total class strength.

Answer 1

let g be no. of girls
b be no. of boys
g+8=b
b:g=7:5
=> b/g=7/5
b= 7g/5
we know g+8 =b
g+8=7g/5
5g+40=7g
g=20,b =28
total clss strength is 48

Answer 2

Let the number of boys be 7x and girls be 5x

Given, number of boys are 8 more than the number of girls => 5x + 8

A/q,

5x + 8 = 7x

8 = 7x - 5x

2x = 8

x = $\dfrac{8}{2}$

x = 4

Number of boys => 7x => 7 × 4 => 28

Number of girls => 5x => 5 × 4 => 20

Total strength of the class => 20 + 28 => 48