There were 259 children enrolled in the Nora Cooking School in 2020. ³₇ of the children were boys. Additional children joined the cooking school in 2021. For every 3 boys who joined the cooking school, 2 girls joined the cooking school. If there was an equal number of girls and boys in 2021, how many girls joined the school in that year?

	Boys	Girls
Before	111	148
Change	+ 3 u	+ 2 u
After	111 + 3 u	148 + 2 u

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

Number of boys at first
= ³₇ x 259
= 111

Number of girls at first
= ⁴₇ x 259
= 148

Boys who joined : Girls who joined
3 : 2

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

111 + 3 u = 148 + 2 u
3 u - 2 u = 148 - 111

1 u = 37

Number of girls who joined the school in that year
= 2 u
= 2 x 37
= 74

Answer(s): 74