Ken had $272 and Cody had $134 at first. Each of them bought an identical sweater and an identical dress from the same shop. The dress cost 3 times as much as the sweater. In the end, Ken had 4 times as much money as Cody. What was the cost of the sweater?

	Ken	Cody	Difference
Before	$272	$134	$138
Change	- 1 sweater - 1 dress	- 1 sweater - 1 dress
After	4 u	1 u	3 u

Since Ken and Cody bought the same items, the difference  in their amounts remains the same.

Difference in the amounts that they had
= 4 u - 1 u
= 3 u

3 u = 272 - 134
3 u = 138

1 u = 138 ÷ 3 = 46

Amount that Cody had in the end
= 1 u
= $46

Cost of 1 sweater and 1 dress
= 134 - 1 u
= 134 - 46
= $88

The dress cost 3 times as much as the sweater.

Cost of 1 sweater = 1 p
Cost of 1 dress = 3 p

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

4 p = 88

1 p = 88 ÷ 4 = 22

Cost of the sweater
= 1 p
= $22

Answer(s): $22