There were 154 children enrolled in the Mary Computer School in 2022. ⁵₁₁ of the children were boys. Additional children joined the computer school in 2023. For every 5 boys who joined the computer school, 4 girls joined the computer school. If there was an equal number of girls and boys in 2023, how many girls joined the school in that year?

	Boys	Girls
Before	70	84
Change	+ 5 u	+ 4 u
After	70 + 5 u	84 + 4 u

Fraction of children who are girls
= 1 - ⁵₁₁
= ⁶₁₁

Number of boys at first
= ⁵₁₁ x 154
= 70

Number of girls at first
= ⁶₁₁ x 154
= 84

Boys who joined : Girls who joined
5 : 4

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

70 + 5 u = 84 + 4 u
5 u - 4 u = 84 - 70

1 u = 14

Number of girls who joined the school in that year
= 4 u
= 4 x 14
= 56

Answer(s): 56