Cathy buys a shirt, a vest, a jacket and a dress. The average cost of these items is $33. The total cost of the jacket and the dress is ³₈ of the total cost of the shirt and the vest. If the shirt costs $17.90 and the dress costs $9.20, find the difference in cost between the vest and the jacket.
Total cost of the 4 items
= 4 x 33
= $132

Total cost of the jacket and the dress = 3 u
Total cost of the shirt and the vest = 8 u

Total cost of the 4 items
= 3 u + 8 u
= 11 u

11 u = 132

1 u = 132 ÷ 11 = 12

Total cost of the jacket and the dress
= 3 u
= 3 x 12
= $36

Cost of the jacket
= 36 - 9.20
= $26.80

Total cost of the shirt and the vest
= 8 u
= 8 x 12
= $96

Cost of the vest
= 96 - 17.90
= $78.10

Difference in cost between the vest and the jacket
= 78.10 - 26.80
= $51.30

Answer(s): $51.30