At a zoo, each adult ticket cost $26 and each child ticket cost $9. On Monday, the number of adult tickets sold was 200 less than the number of child tickets. On Tuesday, the number of adult tickets sold decreased by 20% while the number of child tickets sold increased by 5%. If a total of 580 tickets were sold on Tuesday, how much money was collected on Monday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 200	2 u + 200
Change	- 0.2 u	+ 0.05 u + 10
After	0.8 u	1.05 u + 210	1.85 u + 210

20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u 
5% x 1 u = ⁵₁₀₀ x 1 u = 0.05 u
5% x 200 = ⁵₁₀₀ x 200 = 10

Number of tickets sold on Tuesday
= 0.8 u + 1.05 u + 210
= 1.85 u + 210

1.85 u + 210 = 580
1.85 u = 580 - 210
1.85 u = 370

1 u = 370 ÷ 1.85 = 200

Amount collected from adult tickets on Monday
= 1 u x 26
= 200 x 26
= $5200

Amount collected from child tickets on Monday
= 9(1 u + 200)
= 9(200 + 200)
= 9 x 400
= $3600

Total amount collected on Monday
= 5200 + 3600
= $8800

Answer(s):$8800