At a bird park, each adult ticket cost $40 and each child ticket cost $5. On Saturday, the number of adult tickets sold was 78 less than the number of child tickets. On Sunday, the number of adult tickets sold decreased by 30% while the number of child tickets sold increased by 50%. If a total of 997 tickets were sold on Sunday, how much money was collected on Saturday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 78	2 u + 78
Change	- 0.3 u	+ 0.5 u + 39
After	0.7 u	1.5 u + 117	2.2 u + 117

30% x 1 u = ³⁰₁₀₀ x 1 u = 0.3 u 
50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u
50% x 78 = ⁵⁰₁₀₀ x 78 = 39

Number of tickets sold on Sunday
= 0.7 u + 1.5 u + 117
= 2.2 u + 117

2.2 u + 117 = 997
2.2 u = 997 - 117
2.2 u = 880

1 u = 880 ÷ 2.2 = 400

Amount collected from adult tickets on Saturday
= 1 u x 40
= 400 x 40
= $16000

Amount collected from child tickets on Saturday
= 5(1 u + 78)
= 5(400 + 78)
= 5 x 478
= $2390

Total amount collected on Saturday
= 16000 + 2390
= $18390

Answer(s):$18390