Natalie buys a sweater, a shirt, a jacket and a skirt. The average cost of these items is $28. The total cost of the jacket and the skirt is ²₅ of the total cost of the sweater and the shirt. If the sweater costs $11.20 and the skirt costs $12.80, find the difference in cost between the shirt and the jacket.
Total cost of the 4 items
= 4 x 28
= $112

Total cost of the jacket and the skirt = 2 u
Total cost of the sweater and the shirt = 5 u

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

7 u = 112

1 u = 112 ÷ 7 = 16

Total cost of the jacket and the skirt
= 2 u
= 2 x 16
= $32

Cost of the jacket
= 32 - 12.80
= $19.20

Total cost of the sweater and the shirt
= 5 u
= 5 x 16
= $80

Cost of the shirt
= 80 - 11.20
= $68.80

Difference in cost between the shirt and the jacket
= 68.80 - 19.20
= $49.60

Answer(s): $49.60