At a safari park, each adult ticket cost $21 and each child ticket cost $5. On Thursday, the number of adult tickets sold was 85 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 35% while the number of child tickets sold increased by 40%. If a total of 1554 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 85	2 u + 85
Change	- 0.35 u	+ 0.4 u + 34
After	0.65 u	1.4 u + 119	2.05 u + 119

35% x 1 u = ³⁵₁₀₀ x 1 u = 0.35 u 
40% x 1 u = ⁴⁰₁₀₀ x 1 u = 0.4 u
40% x 85 = ⁴⁰₁₀₀ x 85 = 34

Number of tickets sold on Friday
= 0.65 u + 1.4 u + 119
= 2.05 u + 119

2.05 u + 119 = 1554
2.05 u = 1554 - 119
2.05 u = 1435

1 u = 1435 ÷ 2.05 = 700

Amount collected from adult tickets on Thursday
= 1 u x 21
= 700 x 21
= $14700

Amount collected from child tickets on Thursday
= 5(1 u + 85)
= 5(700 + 85)
= 5 x 785
= $3925

Total amount collected on Thursday
= 14700 + 3925
= $18625

Answer(s):$18625