Question

The ratio of boys and girls attending the school assembly 7:8. If there are 640 girls in the assembly, how many boys are there?

Answer 1

8x=640
x=80
7x=80*7=560.
So number of boys are 560.

Answer 2

let the no. x
8x =640
x=640/8=80
so..boys are 7*80=560