Rachel buys a jumpsuit, a vest, a dress and a coat. The average cost of these items is $36. The total cost of the dress and the coat is ³₅ of the total cost of the jumpsuit and the vest. If the jumpsuit costs $16.90 and the coat costs $18.70, find the difference in cost between the vest and the dress.
Total cost of the 4 items
= 4 x 36
= $144

Total cost of the dress and the coat = 3 u
Total cost of the jumpsuit and the vest = 5 u

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

8 u = 144

1 u = 144 ÷ 8 = 18

Total cost of the dress and the coat
= 3 u
= 3 x 18
= $54

Cost of the dress
= 54 - 18.70
= $35.30

Total cost of the jumpsuit and the vest
= 5 u
= 5 x 18
= $90

Cost of the vest
= 90 - 16.90
= $73.10

Difference in cost between the vest and the dress
= 73.10 - 35.30
= $37.80

Answer(s): $37.80