On Wednesday, 640 more men than women attended a concert. On Thursday, the number of men decreased by 20% and the number of women increased by 70%. 1112 audience attended the concert on Thursday. If each ticket cost $18, how much money was collected from the sale of concert tickets to all the women?

	Men		Women
Comparing between the men and the women at first	640 more
Before	5x2	+ 640	10x1
Change	- 1x2	- 128	+ 7x1
After	4x2	+ 512	17x1

	Men		Women
Before	10 u + 640		10 u
Change	- 2 u - 128		+ 7 u
After	8 u + 512		17 u

20% = ²⁰₁₀₀ = ¹₅

70% = ⁷⁰₁₀₀ = ⁷₁₀

20% x 640
= ²⁰₁₀₀ x 640
= 128

640 - 128 = 512

Total number of tickets sold on Thursday 
= 8 u + 512 + 17 u
= 25 u + 512 

25 u + 512 = 1112
25 u = 1112 - 512
25 u = 600

1 u = 600 ÷ 25 = 24

Total number of tickets sold to all the women
= 10 u + 17 u
= 27 u 
= 27 x 24
= 648

Amount collected from the sale of concert tickets to all the women
= 648 x 18
= $11664

Answer(s): $11664