Zane and Japheth had $116 and $59 respectively. Each of them bought a shirt and a sweater at the same price. The cost of the shirt was 3 times as much as the sweater. In the end, Zane had 4 times as much money as Japheth. What was the difference between the cost of the sweater and the shirt?

	Zane	Japheth	Difference
Before	$116	$59	$57
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Zane and Japheth 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 = 116 - 59
3 u = 57

1 u = 57 ÷ 3 = 19

Cost of 1 shirt = 3 p
Cost of 1 sweater = 1 p

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

4 p = 59 - 19
4 p = 40

1 p = 40 ÷ 4 = 10

Difference in the cost between the shirt and the sweater
= 3 p - 1 p
= 2 p
= 2 x 10
= $20

Answer(s): $20