Answer:
30 minutes
Step-by-step explanation:
If she can pick 1/6 cup of blueberries in 2 minutes, then in 1 minute she can pick (1/6) / 2 = 1/12 cup of blueberries
As she needs 2 1/2, or 2.5 cups of blueberries for the pie, she would need to pick for a total amount of time of
2.5 / (1/12) = 2.5*12 = 30 minutes