Pamela buys a vest, a sweater, a blouse and a jacket. The average cost of these items is $22. The total cost of the blouse and the jacket is ³₅ of the total cost of the vest and the sweater. If the vest costs $19.90 and the jacket costs $10.30, find the difference in cost between the sweater and the blouse.
Total cost of the 4 items
= 4 x 22
= $88

Total cost of the blouse and the jacket = 3 u
Total cost of the vest and the sweater = 5 u

Total cost of the 4 items
= 3 u + 5 u
= 8 u

8 u = 88

1 u = 88 ÷ 8 = 11

Total cost of the blouse and the jacket
= 3 u
= 3 x 11
= $33

Cost of the blouse
= 33 - 10.30
= $22.70

Total cost of the vest and the sweater
= 5 u
= 5 x 11
= $55

Cost of the sweater
= 55 - 19.90
= $35.10

Difference in cost between the sweater and the blouse
= 35.10 - 22.70
= $12.40

Answer(s): $12.40