Erika buys a skirt, a windbreaker, a coat and a jacket. The average cost of these items is $40. The total cost of the coat and the jacket is ³₅ of the total cost of the skirt and the windbreaker. If the skirt costs $11.20 and the jacket costs $9.40, find the difference in cost between the windbreaker and the coat.
Total cost of the 4 items
= 4 x 40
= $160

Total cost of the coat and the jacket = 3 u
Total cost of the skirt and the windbreaker = 5 u

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

8 u = 160

1 u = 160 ÷ 8 = 20

Total cost of the coat and the jacket
= 3 u
= 3 x 20
= $60

Cost of the coat
= 60 - 9.40
= $50.60

Total cost of the skirt and the windbreaker
= 5 u
= 5 x 20
= $100

Cost of the windbreaker
= 100 - 11.20
= $88.80

Difference in cost between the windbreaker and the coat
= 88.80 - 50.60
= $38.20

Answer(s): $38.20