Question

The ratio of boys to girls on a school trip was 5:7 there were 56 girls how many boys were on the school trip

Answer 1

5/7 = x/56....5 boys to 7 girls = x boys to 56 girls
cross multiply
(7)(x) = (56)(5)
7x = 280
x = 280/7
x = 40......there were 40 boys on the school trip

Answer 2

Equation will be like;
5:7::x:56
5/7=x/56
x=5/7*56
x=40