Xuan buys a jumpsuit, a windbreaker, a blouse and a jacket. The average cost of these items is $20. The total cost of the blouse and the jacket is ³₅ of the total cost of the jumpsuit and the windbreaker. If the jumpsuit costs $15.60 and the jacket costs $6.90, find the difference in cost between the windbreaker and the blouse.
Total cost of the 4 items
= 4 x 20
= $80

Total cost of the blouse and the jacket = 3 u
Total cost of the jumpsuit and the windbreaker = 5 u

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

8 u = 80

1 u = 80 ÷ 8 = 10

Total cost of the blouse and the jacket
= 3 u
= 3 x 10
= $30

Cost of the blouse
= 30 - 6.90
= $23.10

Total cost of the jumpsuit and the windbreaker
= 5 u
= 5 x 10
= $50

Cost of the windbreaker
= 50 - 15.60
= $34.40

Difference in cost between the windbreaker and the blouse
= 34.40 - 23.10
= $11.30

Answer(s): $11.30