Mark and Zane had $104 and $89 respectively. Each of them bought a jacket and a cardigan at the same price. The cost of the jacket was 3 times as much as the cardigan. In the end, Mark had 4 times as much money as Zane. What was the difference between the cost of the cardigan and the jacket?

	Mark	Zane	Difference
Before	$104	$89	$15
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Mark and Zane 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 = 104 - 89
3 u = 15

1 u = 15 ÷ 3 = 5

Cost of 1 jacket = 3 p
Cost of 1 cardigan = 1 p

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

4 p = 89 - 5
4 p = 84

1 p = 84 ÷ 4 = 21

Difference in the cost between the jacket and the cardigan
= 3 p - 1 p
= 2 p
= 2 x 21
= $42

Answer(s): $42