Question

The ratio of number of girl to the number of boys in a class is 7:5. If there are 15 boys in the class,then the number of girls in the class is
(a)14

(b)21

(c)28

(d)36​

Answer 1

Answer:

(b) 21 girls

Explanation:

Taking the unknown as x,

Ratio of the number of girls to boys = 7:5 = 7x, 5x

Number of boys in the class = 15 = 5x

The value of x =

⇒ 5x = 15

⇒ x = 15/5

⇒ x = 3

The number of girls in the class =

⇒ 7x

⇒ 7 * 3

⇒ 21 girls

Hence, the number of girls in the class are 21.