Dylan and Ian had $85 and $57 respectively. Each of them bought a blouse and a cardigan at the same price. The cost of the blouse was 4 times as much as the cardigan. In the end, Dylan had 5 times as much money as Ian. What was the difference between the cost of the cardigan and the blouse?

	Dylan	Ian	Difference
Before	$85	$57	$28
Change	- 5 p	- 5 p
After	5 u	1 u	4 u

Since Dylan and Ian 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 = 85 - 57
4 u = 28

1 u = 28 ÷ 4 = 7

Cost of 1 blouse = 4 p
Cost of 1 cardigan = 1 p

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

5 p = 57 - 7
5 p = 50

1 p = 50 ÷ 5 = 10

Difference in the cost between the blouse and the cardigan
= 4 p - 1 p
= 3 p
= 3 x 10
= $30

Answer(s): $30