Answer:
candy bar = 60¢
pack of gum = 35¢
Set up a system:
c = candy bar
g = pack of gum
4c + g = 2.75 Dean's purchase
2c + 3g = 2.25 Robin's purchase
Solve for g:
2(2c + 3g) = 2(2.25)
4c + 6g = 4.50
4c + g = 2.75 Subtract equations
5g = 1.75
g = 0.35
Solve for c:
2c + 3g = 2.25
2c + 3(0.35) = 2.25
2c + 1.05 = 2.25
2c = 1.20
c = 0.6