There are 80 cherries in a pound and she needs 3 pounds to make a pie so she needs 80*3 = <<80*3=240>>240 cherries
It takes her 10 minutes to pit a unit of 20 cherries. She has 240/20 = <<240/20=12>>12 units of cherries to pit
It takes 10 minutes to pit a unit of cherries and she has 12 units so it will take her 10*12 = <<10*12=120>>120 minutes
60 minutes are in 1 hour and it takes her 120 minutes so that’s 120/60 = <<120/60=2>>2 hours
#### 2