There were 110 children enrolled in the Mary Gym School in 2023. ⁴₁₁ of the children were boys. Additional children joined the gym school in 2024. For every 4 boys who joined the gym school, 3 girls joined the gym school. If there was an equal number of girls and boys in 2024, how many girls joined the school in that year?

	Boys	Girls
Before	40	70
Change	+ 4 u	+ 3 u
After	40 + 4 u	70 + 3 u

Fraction of children who are girls
= 1 - ⁴₁₁
= ⁷₁₁

Number of boys at first
= ⁴₁₁ x 110
= 40

Number of girls at first
= ⁷₁₁ x 110
= 70

Boys who joined : Girls who joined
4 : 3

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

40 + 4 u = 70 + 3 u
4 u - 3 u = 70 - 40

1 u = 30

Number of girls who joined the school in that year
= 3 u
= 3 x 30
= 90

Answer(s): 90