Xuan buys a jumpsuit, a jacket, a blazer and a dress. The average cost of these items is $45. The total cost of the blazer and the dress is ⁴₅ of the total cost of the jumpsuit and the jacket. If the jumpsuit costs $11.10 and the dress costs $5.70, find the difference in cost between the jacket and the blazer.
Total cost of the 4 items
= 4 x 45
= $180

Total cost of the blazer and the dress = 4 u
Total cost of the jumpsuit and the jacket = 5 u

Total cost of the 4 items
= 4 u + 5 u
= 9 u

9 u = 180

1 u = 180 ÷ 9 = 20

Total cost of the blazer and the dress
= 4 u
= 4 x 20
= $80

Cost of the blazer
= 80 - 5.70
= $74.30

Total cost of the jumpsuit and the jacket
= 5 u
= 5 x 20
= $100

Cost of the jacket
= 100 - 11.10
= $88.90

Difference in cost between the jacket and the blazer
= 88.90 - 74.30
= $14.60

Answer(s): $14.60