At a park, each adult ticket cost $25 and each child ticket cost $10. On Wednesday, the number of adult tickets sold was 100 less than the number of child tickets. On Thursday, the number of adult tickets sold decreased by 50% while the number of child tickets sold increased by 20%. If a total of 970 tickets were sold on Thursday, how much money was collected on Wednesday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 100	2 u + 100
Change	- 0.5 u	+ 0.2 u + 20
After	0.5 u	1.2 u + 120	1.7 u + 120

50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u 
20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u
20% x 100 = ²⁰₁₀₀ x 100 = 20

Number of tickets sold on Thursday
= 0.5 u + 1.2 u + 120
= 1.7 u + 120

1.7 u + 120 = 970
1.7 u = 970 - 120
1.7 u = 850

1 u = 850 ÷ 1.7 = 500

Amount collected from adult tickets on Wednesday
= 1 u x 25
= 500 x 25
= $12500

Amount collected from child tickets on Wednesday
= 10(1 u + 100)
= 10(500 + 100)
= 10 x 600
= $6000

Total amount collected on Wednesday
= 12500 + 6000
= $18500

Answer(s):$18500