At a bird park, each adult ticket cost $24 and each child ticket cost $18. On Thursday, the number of adult tickets sold was 195 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 25% while the number of child tickets sold increased by 20%. If a total of 1209 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 195	2 u + 195
Change	- 0.25 u	+ 0.2 u + 39
After	0.75 u	1.2 u + 234	1.95 u + 234

25% x 1 u = ²⁵₁₀₀ x 1 u = 0.25 u 
20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u
20% x 195 = ²⁰₁₀₀ x 195 = 39

Number of tickets sold on Friday
= 0.75 u + 1.2 u + 234
= 1.95 u + 234

1.95 u + 234 = 1209
1.95 u = 1209 - 234
1.95 u = 975

1 u = 975 ÷ 1.95 = 500

Amount collected from adult tickets on Thursday
= 1 u x 24
= 500 x 24
= $12000

Amount collected from child tickets on Thursday
= 18(1 u + 195)
= 18(500 + 195)
= 18 x 695
= $12510

Total amount collected on Thursday
= 12000 + 12510
= $24510

Answer(s):$24510