At a zoo, each adult ticket cost $36 and each child ticket cost $15. On Thursday, the number of adult tickets sold was 80 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 20% while the number of child tickets sold increased by 50%. If a total of 1730 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 80	2 u + 80
Change	- 0.2 u	+ 0.5 u + 40
After	0.8 u	1.5 u + 120	2.3 u + 120

20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u 
50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u
50% x 80 = ⁵⁰₁₀₀ x 80 = 40

Number of tickets sold on Friday
= 0.8 u + 1.5 u + 120
= 2.3 u + 120

2.3 u + 120 = 1730
2.3 u = 1730 - 120
2.3 u = 1610

1 u = 1610 ÷ 2.3 = 700

Amount collected from adult tickets on Thursday
= 1 u x 36
= 700 x 36
= $25200

Amount collected from child tickets on Thursday
= 15(1 u + 80)
= 15(700 + 80)
= 15 x 780
= $11700

Total amount collected on Thursday
= 25200 + 11700
= $36900

Answer(s):$36900