Question

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

Answer 1

Given ratio = 3:7

Let number of girls be = 3x

Number of boys be = 7x

Total number of people = 30

As per given condition :-

$3x + 7x = 30 \\ \\ 10x = 30 \\ \\ x = \frac{30}{10} \\ \\ x = 3$

So,

Total number of girls = 3x

= 3 × 3 = 9

Total number of boys = 7x

= 7 × 3 = 21

Hope it helps.

Answer 2

Given,

Total = 30 girls and boys are there

Their ratio = 3:7 (Girls:Boys)

So, let suppose the no. of girls and boys be 3x and 7x respectively.

A.T.Q, we have:

3x + 7x = 30

or, 10x = 30

or, x = $\frac{30}{10}$

$\boxed{x = 3}$

Therefore,

Total no. of Girls = 3x

3 × 3 = 9

Total no. of Boys = 7x

7 × 3 = 21