At a zoo, each adult ticket cost $27 and each child ticket cost $16. On Friday, the number of adult tickets sold was 200 less than the number of child tickets. On Saturday, the number of adult tickets sold decreased by 45% while the number of child tickets sold increased by 20%. If a total of 590 tickets were sold on Saturday, how much money was collected on Friday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 200	2 u + 200
Change	- 0.45 u	+ 0.2 u + 40
After	0.55 u	1.2 u + 240	1.75 u + 240

45% x 1 u = ⁴⁵₁₀₀ x 1 u = 0.45 u 
20% x 1 u = ²⁰₁₀₀ x 1 u = 0.2 u
20% x 200 = ²⁰₁₀₀ x 200 = 40

Number of tickets sold on Saturday
= 0.55 u + 1.2 u + 240
= 1.75 u + 240

1.75 u + 240 = 590
1.75 u = 590 - 240
1.75 u = 350

1 u = 350 ÷ 1.75 = 200

Amount collected from adult tickets on Friday
= 1 u x 27
= 200 x 27
= $5400

Amount collected from child tickets on Friday
= 16(1 u + 200)
= 16(200 + 200)
= 16 x 400
= $6400

Total amount collected on Friday
= 5400 + 6400
= $11800

Answer(s):$11800