Zane and Albert had $160 and $140 respectively. Each of them bought a sweater and a cardigan at the same price. The cost of the sweater was 4 times as much as the cardigan. In the end, Zane had 3 times as much money as Albert. What was the difference between the cost of the cardigan and the sweater?

	Zane	Albert	Difference
Before	$160	$140	$20
Change	- 5 p	- 5 p
After	3 u	1 u	2 u

Since Zane and Albert 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 = 160 - 140
2 u = 20

1 u = 20 ÷ 2 = 10

Cost of 1 sweater = 4 p
Cost of 1 cardigan = 1 p

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

5 p = 140 - 10
5 p = 130

1 p = 130 ÷ 5 = 26

Difference in the cost between the sweater and the cardigan
= 4 p - 1 p
= 3 p
= 3 x 26
= $78

Answer(s): $78