Find each unit price. Which is the better buy? Explain.
Electrical wire:
$1.49 for 3 ft.
$.69 for 18 in.
1.49/3 = 0.50 per foot
0.69/1.5 = 0.46 per foot
.69 is the better buy
1.49/3 = x/1
cross multiply
3x = 1.49
x = 1.49/3
x = 0.496 (rounds to 50 cents per foot)
.69/18 = x/1
cross multiply
18x = .69
x = .69/18
x = .038 per inch
12 inches in a foot
x = .038(12) = 0.456 (rounds to 46 cents per foot)
divide cost/quantity
$1.49/3ft = $0.4967/ft
and similarly for the other one. Then compare