Simon and Oscar had $120 and $100 respectively. Each of them bought a hoodie and a cardigan at the same price. The cost of the hoodie was 4 times as much as the cardigan. In the end, Simon had 3 times as much money as Oscar. What was the difference between the cost of the cardigan and the hoodie?

	Simon	Oscar	Difference
Before	$120	$100	$20
Change	- 5 p	- 5 p
After	3 u	1 u	2 u

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

3 u - 1 u = 120 - 100
2 u = 20

1 u = 20 ÷ 2 = 10

Cost of 1 hoodie = 4 p
Cost of 1 cardigan = 1 p

Total cost of 1 hoodie and 1 cardigan
= 4 p + 1 p
= 5 p

5 p = 100 - 10
5 p = 90

1 p = 90 ÷ 5 = 18

Difference in the cost between the hoodie and the cardigan
= 4 p - 1 p
= 3 p
= 3 x 18
= $54

Answer(s): $54