Gillian buys a jumpsuit, a shirt, a sweater and a vest. The average cost of these items is $24. The total cost of the sweater and the vest is ³₅ of the total cost of the jumpsuit and the shirt. If the jumpsuit costs $11.30 and the vest costs $7.90, find the difference in cost between the shirt and the sweater.
Total cost of the 4 items
= 4 x 24
= $96

Total cost of the sweater and the vest = 3 u
Total cost of the jumpsuit and the shirt = 5 u

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

8 u = 96

1 u = 96 ÷ 8 = 12

Total cost of the sweater and the vest
= 3 u
= 3 x 12
= $36

Cost of the sweater
= 36 - 7.90
= $28.10

Total cost of the jumpsuit and the shirt
= 5 u
= 5 x 12
= $60

Cost of the shirt
= 60 - 11.30
= $48.70

Difference in cost between the shirt and the sweater
= 48.70 - 28.10
= $20.60

Answer(s): $20.60