The total cost of 8 shirts and 8 coats was $384. Tina bought 10 such shirts, 8 such coats and a cardigan for $475. If the total cost of a vest and a shirt was $60, find the difference in cost between the shirt and the vest.
Let 1 S be 1 shirt.
Let 1 C be 1 coat.
Let 1 V be 1 vest.

8 S + 8 C = 384 --- (1)

1 S + 1 C = 384 ÷ 8
1 S + 1 C = 48 --- (2)

1 S + 1 V = 60 --- (3)

10 S + 8 C + 1 V = 475 --- (4)

(4) - (1)
(10 S + 8 C + 1 V) - (8 S + 8 C) = 475 - 384 
10 S - 8 S + 8 C - 8 C + 1 V = 91

2 S + 1 V = 91 --- (5)

(5) - (3)
(2 S + 1 V) - (1 S + 1 V) = 91 - 60
2 S - 1 S + 1 V - 1 V = 31
2 S - 1 S = 31

1 S = 31

From (3)
1 S + 1 V = 60
31 + 1 V = 60

1 V = 60 - 31 = 29

Difference in the cost between the shirt and the vest
= 1 S - 1 V
= 31 - 29
= $2

Answer(s): $2