Question

23.

The ratio of the number of boys to the number of girls in a hall was
3:2 at first. After 30 boys left the hall, the ratio became 2 : 3. How
many boys were there in the hall at first ?

Answer 1

72 boys.

Explanation:

no. of boys (initial) : no. of girls : no. of boys (final)

3 : 2

3 : 2

______________________________________

9 : 6 : 4

9u - 4u = 5u = 30

5u = 30

1u = 30/5 = 8

9u (initial no. of boys) = 8×9

= 72