Cindy buys a skirt, a jumpsuit, a blazer and a jacket. The average cost of these items is $21. The total cost of the blazer and the jacket is ²₅ of the total cost of the skirt and the jumpsuit. If the skirt costs $13.20 and the jacket costs $12.80, find the difference in cost between the jumpsuit and the blazer.
Total cost of the 4 items
= 4 x 21
= $84

Total cost of the blazer and the jacket = 2 u
Total cost of the skirt and the jumpsuit = 5 u

Total cost of the 4 items
= 2 u + 5 u
= 7 u

7 u = 84

1 u = 84 ÷ 7 = 12

Total cost of the blazer and the jacket
= 2 u
= 2 x 12
= $24

Cost of the blazer
= 24 - 12.80
= $11.20

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

Cost of the jumpsuit
= 60 - 13.20
= $46.80

Difference in cost between the jumpsuit and the blazer
= 46.80 - 11.20
= $35.60

Answer(s): $35.60