There were 280 children enrolled in the Cathy Acting School in 2016. ³₇ of the children were boys. Additional children joined the acting school in 2017. For every 3 boys who joined the acting school, 2 girls joined the acting school. If there was an equal number of girls and boys in 2017, how many girls joined the school in that year?

	Boys	Girls
Before	120	160
Change	+ 3 u	+ 2 u
After	120 + 3 u	160 + 2 u

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

Number of boys at first
= ³₇ x 280
= 120

Number of girls at first
= ⁴₇ x 280
= 160

Boys who joined : Girls who joined
3 : 2

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

120 + 3 u = 160 + 2 u
3 u - 2 u = 160 - 120

1 u = 40

Number of girls who joined the school in that year
= 2 u
= 2 x 40
= 80

Answer(s): 80