Kylie buys a shirt, a coat, a blazer and a dress. The average cost of these items is $35. The total cost of the blazer and the dress is ²₅ of the total cost of the shirt and the coat. If the shirt costs $16.50 and the dress costs $17.40, find the difference in cost between the coat and the blazer.
Total cost of the 4 items
= 4 x 35
= $140

Total cost of the blazer and the dress = 2 u
Total cost of the shirt and the coat = 5 u

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

7 u = 140

1 u = 140 ÷ 7 = 20

Total cost of the blazer and the dress
= 2 u
= 2 x 20
= $40

Cost of the blazer
= 40 - 17.40
= $22.60

Total cost of the shirt and the coat
= 5 u
= 5 x 20
= $100

Cost of the coat
= 100 - 16.50
= $83.50

Difference in cost between the coat and the blazer
= 83.50 - 22.60
= $60.90

Answer(s): $60.90