Question

A coat costs $15 more than a dress. Two coats and 4 dresses cost $150. Find the cost of each.

Answer 1

c = coat
d = dress

c = (d + 15)
d = d

2 coats = 2(d + 15)
4 dresses = 4d

2(d + 15) + 4d = 150

Find d
2(d + 15) + 4d = 150
2d + 30 + 4d = 150
2d + 4d + 30 = 150
6d + 30 = 150
6d = 150 - 30
6d / 6 = 120 / 6
d = 20

Substitute 20 for d in  d + 15 to find c
d + 15 
20 + 15
35

c = 35
coat =   $35.00
dress = $20.00