Winnie buys a vest, a sweater, a shirt and a jumpsuit. The average cost of these items is $28. The total cost of the shirt and the jumpsuit is ²₅ of the total cost of the vest and the sweater. If the vest costs $16.10 and the jumpsuit costs $11.40, find the difference in cost between the sweater and the shirt.
Total cost of the 4 items
= 4 x 28
= $112

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

Cost of the shirt
= 32 - 11.40
= $20.60

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

Cost of the sweater
= 80 - 16.10
= $63.90

Difference in cost between the sweater and the shirt
= 63.90 - 20.60
= $43.30

Answer(s): $43.30