Elyse buys a vest, a blouse, a jumpsuit and a sweater. The average cost of these items is $25. The total cost of the jumpsuit and the sweater is ²₃ of the total cost of the vest and the blouse. If the vest costs $13.50 and the sweater costs $12.90, find the difference in cost between the blouse and the jumpsuit.
Total cost of the 4 items
= 4 x 25
= $100

Total cost of the jumpsuit and the sweater = 2 u
Total cost of the vest and the blouse = 3 u

Total cost of the 4 items
= 2 u + 3 u
= 5 u

5 u = 100

1 u = 100 ÷ 5 = 20

Total cost of the jumpsuit and the sweater
= 2 u
= 2 x 20
= $40

Cost of the jumpsuit
= 40 - 12.90
= $27.10

Total cost of the vest and the blouse
= 3 u
= 3 x 20
= $60

Cost of the blouse
= 60 - 13.50
= $46.50

Difference in cost between the blouse and the jumpsuit
= 46.50 - 27.10
= $19.40

Answer(s): $19.40