Tommy and Owen had $164 and $128 respectively. Each of them bought a skirt and a shirt at the same price. The cost of the skirt was 3 times as much as the shirt. In the end, Tommy had 4 times as much money as Owen. What was the difference between the cost of the shirt and the skirt?

	Tommy	Owen	Difference
Before	$164	$128	$36
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Tommy and Owen bought the same items at the same price, the difference in the amounts they had remains unchanged at first and in the end.

4 u - 1 u = 164 - 128
3 u = 36

1 u = 36 ÷ 3 = 12

Cost of 1 skirt = 3 p
Cost of 1 shirt = 1 p

Total cost of 1 skirt and 1 shirt
= 3 p + 1 p
= 4 p

4 p = 128 - 12
4 p = 116

1 p = 116 ÷ 4 = 29

Difference in the cost between the skirt and the shirt
= 3 p - 1 p
= 2 p
= 2 x 29
= $58

Answer(s): $58