The cost of a 20-oz box of cereal is $4.29. A 12-oz box of the same cereal costs $3.59. Which box of cereal is a better buy?

Question

How do you know? Provide evidence to prove your choice is correct.

Answer 1

You have to find out how much each cereal costs per ounce. So you must divide each price by the amount of cereal you get and compare:
$4.08/16oz=$0.255/oz

Can you find the unit price ($/oz) of the remaining 2? You will then compare. The lowest value is the best buy!