At a zoo, each adult ticket cost $31 and each child ticket cost $8. On Friday, the number of adult tickets sold was 136 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 50%. If a total of 409 tickets were sold on Saturday, how much money was collected on Friday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 136	2 u + 136
Change	- 0.45 u	+ 0.5 u + 68
After	0.55 u	1.5 u + 204	2.05 u + 204

45% x 1 u = ⁴⁵₁₀₀ x 1 u = 0.45 u 
50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u
50% x 136 = ⁵⁰₁₀₀ x 136 = 68

Number of tickets sold on Saturday
= 0.55 u + 1.5 u + 204
= 2.05 u + 204

2.05 u + 204 = 409
2.05 u = 409 - 204
2.05 u = 205

1 u = 205 ÷ 2.05 = 100

Amount collected from adult tickets on Friday
= 1 u x 31
= 100 x 31
= $3100

Amount collected from child tickets on Friday
= 8(1 u + 136)
= 8(100 + 136)
= 8 x 236
= $1888

Total amount collected on Friday
= 3100 + 1888
= $4988

Answer(s):$4988