Question

30 girls and boys have planned for a picnic. There is a ratio of
3 girls to 7 boys. How many boys are there?

Answer 1

let,
the no.of girls = 30
      no.of boys = 7x
3x = 30
 x = 30/3
x = 10
no.of boys = 7x = 7 × 10 =70

Answer 2

ratio of girls to boys= 3:7
boys=7x
girls=3x
total=10x
10x=30
x=3

girls=3*3 =9
boys=7*3=21