Riordan buys a jumpsuit, a sweater and a shirt. The average cost of these items is $82. The cost of the shirt is four times the total cost of the jumpsuit and the sweater. If the jumpsuit costs $16, find the difference in cost between the sweater and the shirt.
Total cost of the 3 items
= 3 x 82
= $246

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

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

5 u = 246 

1 u = 246 ÷ 5 = 49.20

Total cost of the jumpsuit and the sweater = $49.20

Cost of the sweater 
= 49.20 - 16
= $33.20

Cost of the shirt
= 4 u
= 4 x 49.20
= $196.80

Difference in cost between the sweater and the shirt
= 196.80 - 33.20
= $163.60

Answer(s): $163.60