Ivory buys a skirt, a blazer, a jumpsuit and a vest. The average cost of these items is $20. The total cost of the jumpsuit and the vest is ³₅ of the total cost of the skirt and the blazer. If the skirt costs $11.80 and the vest costs $11.50, find the difference in cost between the blazer and the jumpsuit.
Total cost of the 4 items
= 4 x 20
= $80

Total cost of the jumpsuit and the vest = 3 u
Total cost of the skirt and the blazer = 5 u

Total cost of the 4 items
= 3 u + 5 u
= 8 u

8 u = 80

1 u = 80 ÷ 8 = 10

Total cost of the jumpsuit and the vest
= 3 u
= 3 x 10
= $30

Cost of the jumpsuit
= 30 - 11.50
= $18.50

Total cost of the skirt and the blazer
= 5 u
= 5 x 10
= $50

Cost of the blazer
= 50 - 11.80
= $38.20

Difference in cost between the blazer and the jumpsuit
= 38.20 - 18.50
= $19.70

Answer(s): $19.70