There were 176 children enrolled in the Xandra Acting School in 2015. ⁵₁₁ of the children were girls. Additional children joined the acting school in 2016. For every 5 girls who joined the acting school, 4 boys joined the acting school. If there was an equal number of boys and girls in 2016, how many boys joined the school in that year?

	Girls	Boys
Before	80	96
Change	+ 5 u	+ 4 u
After	80 + 5 u	96 + 4 u

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

Number of girls at first
= ⁵₁₁ x 176
= 80

Number of boys at first
= ⁶₁₁ x 176
= 96

Girls who joined : Boys who joined
5 : 4

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

80 + 5 u = 96 + 4 u
5 u - 4 u = 96 - 80

1 u = 16

Number of boys who joined the school in that year
= 4 u
= 4 x 16
= 64

Answer(s): 64