Min buys a windbreaker, a blazer, a skirt and a sweater. The average cost of these items is $40. The total cost of the skirt and the sweater is ³₅ of the total cost of the windbreaker and the blazer. If the windbreaker costs $19.80 and the sweater costs $5.70, find the difference in cost between the blazer and the skirt.
Total cost of the 4 items
= 4 x 40
= $160

Total cost of the skirt and the sweater = 3 u
Total cost of the windbreaker and the blazer = 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 skirt and the sweater
= 3 u
= 3 x 20
= $60

Cost of the skirt
= 60 - 5.70
= $54.30

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

Cost of the blazer
= 100 - 19.80
= $80.20

Difference in cost between the blazer and the skirt
= 80.20 - 54.30
= $25.90

Answer(s): $25.90