At a tourist attraction, each adult ticket cost $36 and each child ticket cost $8. On Friday, the number of adult tickets sold was 165 less than the number of child tickets. On Saturday, the number of adult tickets sold decreased by 20% while the number of child tickets sold increased by 40%. If a total of 1331 tickets were sold on Saturday, how much money was collected on Friday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 165	2 u + 165
Change	- 0.2 u	+ 0.4 u + 66
After	0.8 u	1.4 u + 231	2.2 u + 231

20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u 
40% x 1 u = ⁴⁰₁₀₀ x 1 u = 0.4 u
40% x 165 = ⁴⁰₁₀₀ x 165 = 66

Number of tickets sold on Saturday
= 0.8 u + 1.4 u + 231
= 2.2 u + 231

2.2 u + 231 = 1331
2.2 u = 1331 - 231
2.2 u = 1100

1 u = 1100 ÷ 2.2 = 500

Amount collected from adult tickets on Friday
= 1 u x 36
= 500 x 36
= $18000

Amount collected from child tickets on Friday
= 8(1 u + 165)
= 8(500 + 165)
= 8 x 665
= $5320

Total amount collected on Friday
= 18000 + 5320
= $23320

Answer(s):$23320