We can find the unit price of each size by dividing their cost by the amount of coffee each size contains.
• For the 12.3 ounce, we get:
[tex]\frac{2.99}{12.3}=0.24[/tex]The unit price for the 12.3 ounce is $0.24 per ounce
• For the 33.9 ounce:
[tex]\frac{8.74}{33.9}=0.26[/tex]The unit price for the 33.9 ounce is $0.26 per ounce
Then, the 12.3-ounce size is the best buy, since its unit price is the lowest.