The total cost of 9 jumpsuits and 9 shirts was $585. Tina bought 11 such jumpsuits, 9 such shirts and a cardigan for $688. If the total cost of a blouse and a jumpsuit was $67, find the difference in cost between the jumpsuit and the blouse.
Let 1 J be 1 jumpsuit.
Let 1 S be 1 shirt.
Let 1 B be 1 blouse.

9 J + 9 S = 585 --- (1)

1 J + 1 S = 585 ÷ 9
1 J + 1 S = 65 --- (2)

1 J + 1 B = 67 --- (3)

11 J + 9 S + 1 B = 688 --- (4)

(4) - (1)
(11 J + 9 S + 1 B) - (9 J + 9 S) = 688 - 585 
11 J - 9 J + 9 S - 9 S + 1 B = 103

2 J + 1 B = 103 --- (5)

(5) - (3)
(2 J + 1 B) - (1 J + 1 B) = 103 - 67
2 J - 1 J + 1 B - 1 B = 36
2 J - 1 J = 36

1 J = 36

From (3)
1 J + 1 B = 67
36 + 1 B = 67

1 B = 67 - 36 = 31

Difference in the cost between the jumpsuit and the blouse
= 1 J - 1 B
= 36 - 31
= $5

Answer(s): $5