Joelle buys a blouse, a sweater, a windbreaker and a vest. The average cost of these items is $28. The total cost of the windbreaker and the vest is ³₅ of the total cost of the blouse and the sweater. If the blouse costs $14.10 and the vest costs $10.80, find the difference in cost between the sweater and the windbreaker.
Total cost of the 4 items
= 4 x 28
= $112

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

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

8 u = 112

1 u = 112 ÷ 8 = 14

Total cost of the windbreaker and the vest
= 3 u
= 3 x 14
= $42

Cost of the windbreaker
= 42 - 10.80
= $31.20

Total cost of the blouse and the sweater
= 5 u
= 5 x 14
= $70

Cost of the sweater
= 70 - 14.10
= $55.90

Difference in cost between the sweater and the windbreaker
= 55.90 - 31.20
= $24.70

Answer(s): $24.70