Betty buys a vest, a blouse, a blazer and a windbreaker. The average cost of these items is $36. The total cost of the blazer and the windbreaker is ³₅ of the total cost of the vest and the blouse. If the vest costs $15.40 and the windbreaker costs $8.80, find the difference in cost between the blouse and the blazer.
Total cost of the 4 items
= 4 x 36
= $144

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

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

8 u = 144

1 u = 144 ÷ 8 = 18

Total cost of the blazer and the windbreaker
= 3 u
= 3 x 18
= $54

Cost of the blazer
= 54 - 8.80
= $45.20

Total cost of the vest and the blouse
= 5 u
= 5 x 18
= $90

Cost of the blouse
= 90 - 15.40
= $74.60

Difference in cost between the blouse and the blazer
= 74.60 - 45.20
= $29.40

Answer(s): $29.40