¹₉ of the guests at a zoo were boys. 80% of the remaining guests were girls and the rest were adults. The number of girls was 190 more than the total number of boys and adults. After some girls left the zoo, 50% of the guests that remained were girls. How many girls left the zoo?

Boys	Adults	Girls	Total
1x5	8x5		9x5
	1x8	4x8
5	8	32	45

	Boys and adults	Girls
Before	13x1 = 13 u	32x1 = 32 u
Change		- 19 u
After	1x13 = 13 u	1x13 = 13 u

80% = ⁸⁰₁₀₀ = ⁴₅
Adults : Girls = 1 : 4

The total number of adults and girls at first is repeated.  Make the total number of adults at first the same. LCM of 8 and 5 is 40.

50% = ⁵⁰₁₀₀ = ¹₂

When some girls left, the total number of boys and adults remains unchanged. Make the total number of boys and adults the same. LCM of 13 and 1 is 13.

The number of girls was 190 more than the total number of boys and adults at first.

Number of more girls than the total number of boys and adults at first
= 32 u - 13 u
= 19 u

19 u = 190

1 u = 190 ÷ 19 = 10

Number of girls who left the zoo
= 32 u - 13 u
= 19 u
= 19 x 10
= 190

Answer(s): 190