Ian and John had $125 and $81 respectively. Each of them bought a skirt and a shirt at the same price. The cost of the skirt was 4 times as much as the shirt. In the end, Ian had 5 times as much money as John. What was the difference between the cost of the shirt and the skirt?

	Ian	John	Difference
Before	$125	$81	$44
Change	- 5 p	- 5 p
After	5 u	1 u	4 u

Since Ian and John 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 = 125 - 81
4 u = 44

1 u = 44 ÷ 4 = 11

Cost of 1 skirt = 4 p
Cost of 1 shirt = 1 p

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

5 p = 81 - 11
5 p = 70

1 p = 70 ÷ 5 = 14

Difference in the cost between the skirt and the shirt
= 4 p - 1 p
= 3 p
= 3 x 14
= $42

Answer(s): $42