At a museum, each adult ticket cost $30 and each child ticket cost $17. On Friday, the number of adult tickets sold was 172 less than the number of child tickets. On Saturday, the number of adult tickets sold decreased by 35% while the number of child tickets sold increased by 25%. If a total of 975 tickets were sold on Saturday, how much money was collected on Friday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 172	2 u + 172
Change	- 0.35 u	+ 0.25 u + 43
After	0.65 u	1.25 u + 215	1.9 u + 215

35% x 1 u = ³⁵₁₀₀ x 1 u = 0.35 u 
25% x 1 u = ²⁵₁₀₀ x 1 u = 0.25 u
25% x 172 = ²⁵₁₀₀ x 172 = 43

Number of tickets sold on Saturday
= 0.65 u + 1.25 u + 215
= 1.9 u + 215

1.9 u + 215 = 975
1.9 u = 975 - 215
1.9 u = 760

1 u = 760 ÷ 1.9 = 400

Amount collected from adult tickets on Friday
= 1 u x 30
= 400 x 30
= $12000

Amount collected from child tickets on Friday
= 17(1 u + 172)
= 17(400 + 172)
= 17 x 572
= $9724

Total amount collected on Friday
= 12000 + 9724
= $21724

Answer(s):$21724