Riordan and Will had $132 and $117 respectively. Each of them bought a hoodie and a cardigan at the same price. The cost of the hoodie was 3 times as much as the cardigan. In the end, Riordan had 4 times as much money as Will. What was the difference between the cost of the cardigan and the hoodie?

	Riordan	Will	Difference
Before	$132	$117	$15
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Riordan and Will 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 = 132 - 117
3 u = 15

1 u = 15 ÷ 3 = 5

Cost of 1 hoodie = 3 p
Cost of 1 cardigan = 1 p

Total cost of 1 hoodie and 1 cardigan
= 3 p + 1 p
= 4 p

4 p = 117 - 5
4 p = 112

1 p = 112 ÷ 4 = 28

Difference in the cost between the hoodie and the cardigan
= 3 p - 1 p
= 2 p
= 2 x 28
= $56

Answer(s): $56