There were 231 adults enrolled in the Barbara Cooking School in 2017. ⁵₁₁ of the adults were men. Additional adults joined the cooking school in 2018. For every 5 men who joined the cooking school, 4 women joined the cooking school. If there was an equal number of women and men in 2018, how many women joined the school in that year?

	Men	Women
Before	105	126
Change	+ 5 u	+ 4 u
After	105 + 5 u	126 + 4 u

Fraction of adults who are women
= 1 - ⁵₁₁
= ⁶₁₁

Number of men at first
= ⁵₁₁ x 231
= 105

Number of women at first
= ⁶₁₁ x 231
= 126

Men who joined : Women who joined
5 : 4

The number of women and men in the end is the same.

105 + 5 u = 126 + 4 u
5 u - 4 u = 126 - 105

1 u = 21

Number of women who joined the school in that year
= 4 u
= 4 x 21
= 84

Answer(s): 84