At a bird park, each adult ticket cost $39 and each child ticket cost $6. On Thursday, the number of adult tickets sold was 140 less than the number of child tickets. On Friday, the number of adult tickets sold decreased by 30% while the number of child tickets sold increased by 25%. If a total of 1540 tickets were sold on Friday, how much money was collected on Thursday?

	Adult tickets	Child tickets	Total tickets
Before	1 u	1 u + 140	2 u + 140
Change	- 0.3 u	+ 0.25 u + 35
After	0.7 u	1.25 u + 175	1.95 u + 175

30% x 1 u = ³⁰₁₀₀ x 1 u = 0.3 u 
25% x 1 u = ²⁵₁₀₀ x 1 u = 0.25 u
25% x 140 = ²⁵₁₀₀ x 140 = 35

Number of tickets sold on Friday
= 0.7 u + 1.25 u + 175
= 1.95 u + 175

1.95 u + 175 = 1540
1.95 u = 1540 - 175
1.95 u = 1365

1 u = 1365 ÷ 1.95 = 700

Amount collected from adult tickets on Thursday
= 1 u x 39
= 700 x 39
= $27300

Amount collected from child tickets on Thursday
= 6(1 u + 140)
= 6(700 + 140)
= 6 x 840
= $5040

Total amount collected on Thursday
= 27300 + 5040
= $32340

Answer(s):$32340