Asher had $330 and David had $138 at first. Each of them bought an identical cardigan and an identical jacket from the same shop. The jacket cost 5 times as much as the cardigan. In the end, Asher had 5 times as much money as David. What was the cost of the cardigan?

	Asher	David	Difference
Before	$330	$138	$192
Change	- 1 cardigan - 1 jacket	- 1 cardigan - 1 jacket
After	5 u	1 u	4 u

Since Asher and David bought the same items, the difference  in their amounts remains the same.

Difference in the amounts that they had
= 5 u - 1 u
= 4 u

4 u = 330 - 138
4 u = 192

1 u = 192 ÷ 4 = 48

Amount that David had in the end
= 1 u
= $48

Cost of 1 cardigan and 1 jacket
= 138 - 1 u
= 138 - 48
= $90

The jacket cost 5 times as much as the cardigan.

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

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

6 p = 90

1 p = 90 ÷ 6 = 15

Cost of the cardigan
= 1 p
= $15

Answer(s): $15