There were 252 children enrolled in the Elyse Dancing School in 2018. ³₇ of the children were girls. Additional children joined the dancing school in 2019. For every 3 girls who joined the dancing school, 2 boys joined the dancing school. If there was an equal number of boys and girls in 2019, how many boys joined the school in that year?

	Girls	Boys
Before	108	144
Change	+ 3 u	+ 2 u
After	108 + 3 u	144 + 2 u

Fraction of children who are boys
= 1 - ³₇
= ⁴₇

Number of girls at first
= ³₇ x 252
= 108

Number of boys at first
= ⁴₇ x 252
= 144

Girls who joined : Boys who joined
3 : 2

The number of boys and girls in the end is the same.

108 + 3 u = 144 + 2 u
3 u - 2 u = 144 - 108

1 u = 36

Number of boys who joined the school in that year
= 2 u
= 2 x 36
= 72

Answer(s): 72