Lamar bought 20 pounds of dog food for $4.99 for his dog, Buster. The next day, the shop down the street offered 50 pounds of the same brand of dog food for $12.50. Did Lamar get a better deal? ... ?

To calculate what is better deal we need to calculate how much 1 pound of dog food costs at both shops.

First shop:

4.99/20 = 0.2495$/pound

Second shop:

12.50/50 = 0.25$/pound

This means that first shop had slightly better deal since at that place pound was a bit less expensive.