Pierre and Carl had $240 and $200 respectively. Each of them bought a cardigan and a jacket at the same price. The cost of the cardigan was 5 times as much as the jacket. In the end, Pierre had 3 times as much money as Carl. What was the difference between the cost of the jacket and the cardigan?

	Pierre	Carl	Difference
Before	$240	$200	$40
Change	- 6 p	- 6 p
After	3 u	1 u	2 u

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

3 u - 1 u = 240 - 200
2 u = 40

1 u = 40 ÷ 2 = 20

Cost of 1 cardigan = 5 p
Cost of 1 jacket = 1 p

Total cost of 1 cardigan and 1 jacket
= 5 p + 1 p
= 6 p

6 p = 200 - 20
6 p = 180

1 p = 180 ÷ 6 = 30

Difference in the cost between the cardigan and the jacket
= 5 p - 1 p
= 4 p
= 4 x 30
= $120

Answer(s): $120