Emma buys a dress, a shirt, a jumpsuit and a coat. The average cost of these items is $36. The total cost of the jumpsuit and the coat is ³₅ of the total cost of the dress and the shirt. If the dress costs $15.20 and the coat costs $16.70, find the difference in cost between the shirt and the jumpsuit.
Total cost of the 4 items
= 4 x 36
= $144

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

Cost of the jumpsuit
= 54 - 16.70
= $37.30

Total cost of the dress and the shirt
= 5 u
= 5 x 18
= $90

Cost of the shirt
= 90 - 15.20
= $74.80

Difference in cost between the shirt and the jumpsuit
= 74.80 - 37.30
= $37.50

Answer(s): $37.50