On Wednesday, 400 more women than men attended a concert. On Thursday, the number of women decreased by 20% and the number of men increased by 70%. 970 audience attended the concert on Thursday. If each ticket cost $9, how much money was collected from the sale of concert tickets to all the men?

	Women		Men
Comparing between the women and the men at first	400 more
Before	5x2	+ 400	10x1
Change	- 1x2	- 80	+ 7x1
After	4x2	+ 320	17x1

	Women		Men
Before	10 u + 400		10 u
Change	- 2 u - 80		+ 7 u
After	8 u + 320		17 u

20% = ²⁰₁₀₀ = ¹₅

70% = ⁷⁰₁₀₀ = ⁷₁₀

20% x 400
= ²⁰₁₀₀ x 400
= 80

400 - 80 = 320

Total number of tickets sold on Thursday 
= 8 u + 320 + 17 u
= 25 u + 320 

25 u + 320 = 970
25 u = 970 - 320
25 u = 650

1 u = 650 ÷ 25 = 26

Total number of tickets sold to all the men
= 10 u + 17 u
= 27 u 
= 27 x 26
= 702

Amount collected from the sale of concert tickets to all the men
= 702 x 9
= $6318

Answer(s): $6318