Answer:
96 = x
Step-by-step explanation:
I'm going to use cents instead of dollars because I find decimals and fractions to be cumbersome. I assume you meant $.005 instead of 4.005.
Let x denote the price (in cents) of the 12-ounce can. Then the price of the 16-ounce can is (x + 16) cents, and the price of the 24-ounce can is ((x + 16) + 68), or (x + 84) cents.
The unit price (cents per ounce) of the 12-oz can is x/12
The unit price of the 16-oz can is (x + 16)/16
The unit price of the 24-oz can is (x + 84)/24
You are told that, in terms of x,
(x + 84)/24 = x/12 - 0.5
Multiply both sides by 24:
x + 84 = 2x - 12
Solve for x:
96 = x
So the unit prices (in cents per ounce) are:
12 oz: 96/12 = 8 cents/oz
16 oz: 112/16 = 7 cents/oz
24 oz: 180/24 = 7.5 cents/oz
So the 16 ounce can is the best buy based on lowest unit price.