Question

Mr. Blackwood is buying boxes of snack-size bags of crackers to pack in his family's school lunches.

The first box costs $9.80 and contains 20 bags. The second box contains 30 bags and costs $13.50.



1. Which box is the better buy?

2. Write a mathematical argument that can be used to defend your solution. (Prove your answer in #1 is correct.)

Answer 1

Answer:

1. The second box

2. When you find the unit cost or unit rate, you’ll find that box 2‘s unit cost is 4 cents less than box 1’s. While not much, it can add up after a while.