Vaidev buys a skirt, a windbreaker and a dress. The average cost of these items is $93. The cost of the dress is four times the total cost of the skirt and the windbreaker. If the skirt costs $13, find the difference in cost between the windbreaker and the dress.
Total cost of the 3 items
= 3 x 93
= $279

Total cost of the skirt and the windbreaker = 1 u
Cost of the dress = 4 u

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

5 u = 279 

1 u = 279 ÷ 5 = 55.80

Total cost of the skirt and the windbreaker = $55.80

Cost of the windbreaker 
= 55.80 - 13
= $42.80

Cost of the dress
= 4 u
= 4 x 55.80
= $223.20

Difference in cost between the windbreaker and the dress
= 223.20 - 42.80
= $180.40

Answer(s): $180.40