Xavier buys a skirt, a jumpsuit and a sweater. The average cost of these items is $59. The cost of the sweater is four times the total cost of the skirt and the jumpsuit. If the skirt costs $17, find the difference in cost between the jumpsuit and the sweater.
Total cost of the 3 items
= 3 x 59
= $177

Total cost of the skirt and the jumpsuit = 1 u
Cost of the sweater = 4 u

Total cost of the 3 items 
= 1 u + 4 u
= 5 u

5 u = 177 

1 u = 177 ÷ 5 = 35.40

Total cost of the skirt and the jumpsuit = $35.40

Cost of the jumpsuit 
= 35.40 - 17
= $18.40

Cost of the sweater
= 4 u
= 4 x 35.40
= $141.60

Difference in cost between the jumpsuit and the sweater
= 141.60 - 18.40
= $123.20

Answer(s): $123.20