At a museum, each adult ticket cost $25 and each child ticket cost $10. On Thursday, the number of adult tickets sold was 170 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 10% while the number of child tickets sold increased by 50%. If a total of 2175 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 170	2 u + 170
Change	- 0.1 u	+ 0.5 u + 85
After	0.9 u	1.5 u + 255	2.4 u + 255

10% x 1 u = ¹⁰₁₀₀ x 1 u = 0.1 u 
50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u
50% x 170 = ⁵⁰₁₀₀ x 170 = 85

Number of tickets sold on Friday
= 0.9 u + 1.5 u + 255
= 2.4 u + 255

2.4 u + 255 = 2175
2.4 u = 2175 - 255
2.4 u = 1920

1 u = 1920 ÷ 2.4 = 800

Amount collected from adult tickets on Thursday
= 1 u x 25
= 800 x 25
= $20000

Amount collected from child tickets on Thursday
= 10(1 u + 170)
= 10(800 + 170)
= 10 x 970
= $9700

Total amount collected on Thursday
= 20000 + 9700
= $29700

Answer(s):$29700