Bobby and Vincent had $84 and $52 respectively. Each of them bought a shirt and a cardigan at the same price. The cost of the shirt was 3 times as much as the cardigan. In the end, Bobby had 5 times as much money as Vincent. What was the difference between the cost of the cardigan and the shirt?

	Bobby	Vincent	Difference
Before	$84	$52	$32
Change	- 4 p	- 4 p
After	5 u	1 u	4 u

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

5 u - 1 u = 84 - 52
4 u = 32

1 u = 32 ÷ 4 = 8

Cost of 1 shirt = 3 p
Cost of 1 cardigan = 1 p

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

4 p = 52 - 8
4 p = 44

1 p = 44 ÷ 4 = 11

Difference in the cost between the shirt and the cardigan
= 3 p - 1 p
= 2 p
= 2 x 11
= $22

Answer(s): $22