Julie buys a sweater, a dress, a jumpsuit and a shirt. The average cost of these items is $28. The total cost of the jumpsuit and the shirt is ²₅ of the total cost of the sweater and the dress. If the sweater costs $17.30 and the shirt costs $5.20, find the difference in cost between the dress and the jumpsuit.
Total cost of the 4 items
= 4 x 28
= $112

Total cost of the jumpsuit and the shirt = 2 u
Total cost of the sweater and the dress = 5 u

Total cost of the 4 items
= 2 u + 5 u
= 7 u

7 u = 112

1 u = 112 ÷ 7 = 16

Total cost of the jumpsuit and the shirt
= 2 u
= 2 x 16
= $32

Cost of the jumpsuit
= 32 - 5.20
= $26.80

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

Cost of the dress
= 80 - 17.30
= $62.70

Difference in cost between the dress and the jumpsuit
= 62.70 - 26.80
= $35.90

Answer(s): $35.90