At a safari park, each adult ticket cost $40 and each child ticket cost $10. On Thursday, the number of adult tickets sold was 200 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 40% while the number of child tickets sold increased by 50%. If a total of 930 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 200	2 u + 200
Change	- 0.4 u	+ 0.5 u + 100
After	0.6 u	1.5 u + 300	2.1 u + 300

40% x 1 u = ⁴⁰₁₀₀ x 1 u = 0.4 u 
50% x 1 u = ⁵⁰₁₀₀ x 1 u = 0.5 u
50% x 200 = ⁵⁰₁₀₀ x 200 = 100

Number of tickets sold on Friday
= 0.6 u + 1.5 u + 300
= 2.1 u + 300

2.1 u + 300 = 930
2.1 u = 930 - 300
2.1 u = 630

1 u = 630 ÷ 2.1 = 300

Amount collected from adult tickets on Thursday
= 1 u x 40
= 300 x 40
= $12000

Amount collected from child tickets on Thursday
= 10(1 u + 200)
= 10(300 + 200)
= 10 x 500
= $5000

Total amount collected on Thursday
= 12000 + 5000
= $17000

Answer(s):$17000