Luke and Sam had $128 and $68 respectively. Each of them bought a shirt and a blouse at the same price. The cost of the shirt was 3 times as much as the blouse. In the end, Luke had 4 times as much money as Sam. What was the difference between the cost of the blouse and the shirt?

	Luke	Sam	Difference
Before	$128	$68	$60
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Luke and Sam 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 = 128 - 68
3 u = 60

1 u = 60 ÷ 3 = 20

Cost of 1 shirt = 3 p
Cost of 1 blouse = 1 p

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

4 p = 68 - 20
4 p = 48

1 p = 48 ÷ 4 = 12

Difference in the cost between the shirt and the blouse
= 3 p - 1 p
= 2 p
= 2 x 12
= $24

Answer(s): $24