Reggie buys a shirt, a windbreaker and a vest. The average cost of these items is $77. The cost of the vest is four times the total cost of the shirt and the windbreaker. If the shirt costs $27, find the difference in cost between the windbreaker and the vest.
Total cost of the 3 items
= 3 x 77
= $231

Total cost of the shirt and the windbreaker = 1 u
Cost of the vest = 4 u

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

5 u = 231 

1 u = 231 ÷ 5 = 46.20

Total cost of the shirt and the windbreaker = $46.20

Cost of the windbreaker 
= 46.20 - 27
= $19.20

Cost of the vest
= 4 u
= 4 x 46.20
= $184.80

Difference in cost between the windbreaker and the vest
= 184.80 - 19.20
= $165.60

Answer(s): $165.60