The total cost of 4 jumpsuits and 4 coats was $212. Tina bought 6 such jumpsuits, 4 such coats and a cardigan for $321. If the total cost of a windbreaker and a jumpsuit was $72, find the difference in cost between the jumpsuit and the windbreaker.
Let 1 J be 1 jumpsuit.
Let 1 C be 1 coat.
Let 1 W be 1 windbreaker.

4 J + 4 C = 212 --- (1)

1 J + 1 C = 212 ÷ 4
1 J + 1 C = 53 --- (2)

1 J + 1 W = 72 --- (3)

6 J + 4 C + 1 W = 321 --- (4)

(4) - (1)
(6 J + 4 C + 1 W) - (4 J + 4 C) = 321 - 212 
6 J - 4 J + 4 C - 4 C + 1 W = 109

2 J + 1 W = 109 --- (5)

(5) - (3)
(2 J + 1 W) - (1 J + 1 W) = 109 - 72
2 J - 1 J + 1 W - 1 W = 37
2 J - 1 J = 37

1 J = 37

From (3)
1 J + 1 W = 72
37 + 1 W = 72

1 W = 72 - 37 = 35

Difference in the cost between the jumpsuit and the windbreaker
= 1 J - 1 W
= 37 - 35
= $2

Answer(s): $2