At a bird park, each adult ticket cost $30 and each child ticket cost $14. On Thursday, the number of adult tickets sold was 80 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 1547 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 80	2 u + 80
Change	- 0.35 u	+ 0.4 u + 32
After	0.65 u	1.4 u + 112	2.05 u + 112

35% x 1 u = ³⁵₁₀₀ x 1 u = 0.35 u 
40% x 1 u = ⁴⁰₁₀₀ x 1 u = 0.4 u
40% x 80 = ⁴⁰₁₀₀ x 80 = 32

Number of tickets sold on Friday
= 0.65 u + 1.4 u + 112
= 2.05 u + 112

2.05 u + 112 = 1547
2.05 u = 1547 - 112
2.05 u = 1435

1 u = 1435 ÷ 2.05 = 700

Amount collected from adult tickets on Thursday
= 1 u x 30
= 700 x 30
= $21000

Amount collected from child tickets on Thursday
= 14(1 u + 80)
= 14(700 + 80)
= 14 x 780
= $10920

Total amount collected on Thursday
= 21000 + 10920
= $31920

Answer(s):$31920