Flynn had $320 and Fred had $148 at first. Each of them bought an identical shirt and an identical windbreaker from the same shop. The windbreaker cost 2 times as much as the shirt. In the end, Flynn had 5 times as much money as Fred. What was the cost of the shirt?

	Flynn	Fred	Difference
Before	$320	$148	$172
Change	- 1 shirt - 1 windbreaker	- 1 shirt - 1 windbreaker
After	5 u	1 u	4 u

Since Flynn and Fred bought the same items, the difference  in their amounts remains the same.

Difference in the amounts that they had
= 5 u - 1 u
= 4 u

4 u = 320 - 148
4 u = 172

1 u = 172 ÷ 4 = 43

Amount that Fred had in the end
= 1 u
= $43

Cost of 1 shirt and 1 windbreaker
= 148 - 1 u
= 148 - 43
= $105

The windbreaker cost 2 times as much as the shirt.

Cost of 1 shirt = 1 p
Cost of 1 windbreaker = 2 p

Total cost of 1 shirt and 1 windbreaker
= 1 p + 2 p
= 3 p

3 p = 105

1 p = 105 ÷ 3 = 35

Cost of the shirt
= 1 p
= $35

Answer(s): $35