The total cost of 6 vests and 6 skirts was $312. Tina bought 8 such vests, 6 such skirts and a cardigan for $408. If the total cost of a jumpsuit and a vest was $60, find the difference in cost between the vest and the jumpsuit.
Let 1 V be 1 vest.
Let 1 S be 1 skirt.
Let 1 J be 1 jumpsuit.

6 V + 6 S = 312 --- (1)

1 V + 1 S = 312 ÷ 6
1 V + 1 S = 52 --- (2)

1 V + 1 J = 60 --- (3)

8 V + 6 S + 1 J = 408 --- (4)

(4) - (1)
(8 V + 6 S + 1 J) - (6 V + 6 S) = 408 - 312 
8 V - 6 V + 6 S - 6 S + 1 J = 96

2 V + 1 J = 96 --- (5)

(5) - (3)
(2 V + 1 J) - (1 V + 1 J) = 96 - 60
2 V - 1 V + 1 J - 1 J = 36
2 V - 1 V = 36

1 V = 36

From (3)
1 V + 1 J = 60
36 + 1 J = 60

1 J = 60 - 36 = 24

Difference in the cost between the vest and the jumpsuit
= 1 V - 1 J
= 36 - 24
= $12

Answer(s): $12