Ahmad and Riordan had $175 and $103 respectively. Each of them bought a sweater and a shirt at the same price. The cost of the sweater was 4 times as much as the shirt. In the end, Ahmad had 5 times as much money as Riordan. What was the difference between the cost of the shirt and the sweater?

	Ahmad	Riordan	Difference
Before	$175	$103	$72
Change	- 5 p	- 5 p
After	5 u	1 u	4 u

Since Ahmad and Riordan 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 = 175 - 103
4 u = 72

1 u = 72 ÷ 4 = 18

Cost of 1 sweater = 4 p
Cost of 1 shirt = 1 p

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

5 p = 103 - 18
5 p = 85

1 p = 85 ÷ 5 = 17

Difference in the cost between the sweater and the shirt
= 4 p - 1 p
= 3 p
= 3 x 17
= $51

Answer(s): $51