Roshel buys a sweater, a dress, a shirt and a blouse. The average cost of these items is $32. The total cost of the shirt and the blouse is ³₅ of the total cost of the sweater and the dress. If the sweater costs $15.10 and the blouse costs $7.90, find the difference in cost between the dress and the shirt.
Total cost of the 4 items
= 4 x 32
= $128

Total cost of the shirt and the blouse = 3 u
Total cost of the sweater and the dress = 5 u

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

8 u = 128

1 u = 128 ÷ 8 = 16

Total cost of the shirt and the blouse
= 3 u
= 3 x 16
= $48

Cost of the shirt
= 48 - 7.90
= $40.10

Total cost of the sweater and the dress
= 5 u
= 5 x 16
= $80

Cost of the dress
= 80 - 15.10
= $64.90

Difference in cost between the dress and the shirt
= 64.90 - 40.10
= $24.80

Answer(s): $24.80