Question

2.
There was an equal number of boys and girls in a school hall. After 108 boys
left the hall, the number of girls in the hall became 4 times the number of boys
in the hall. How many pupils were there in the hall at first?
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Answer 1

As per question, number of girls is equal to the number of girls.

Let's consider the number of boys as x,

x = x

4x = x - 108

4x - x = 108

3x = 108

x = 108 ÷ 3

x = 36

Hence, number of boys is equal to 36

Hope it helps