The recipe calls for a pound and a half of strawberries, but I only needed one-third as many blueberries as I did strawberries to make the pie. How many blueberries did I need?

8 ounces

Step-by-step explanation:

First, you should convert the 1 1/2 pounds to ounces. (24 ounces) Once that is converted, you can then divide it by 3 to find how many blueberries you need. (24:3=8) So now you can see that you need 8 ounces of blueberries for the pie.