Oscar and Peter had $124 and $70 respectively. Each of them bought a sweater and a blouse at the same price. The cost of the sweater was 3 times as much as the blouse. In the end, Oscar had 4 times as much money as Peter. What was the difference between the cost of the blouse and the sweater?

	Oscar	Peter	Difference
Before	$124	$70	$54
Change	- 4 p	- 4 p
After	4 u	1 u	3 u

Since Oscar and Peter 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 = 124 - 70
3 u = 54

1 u = 54 ÷ 3 = 18

Cost of 1 sweater = 3 p
Cost of 1 blouse = 1 p

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

4 p = 70 - 18
4 p = 52

1 p = 52 ÷ 4 = 13

Difference in the cost between the sweater and the blouse
= 3 p - 1 p
= 2 p
= 2 x 13
= $26

Answer(s): $26