First find the number of nuts the two busy squirrels gather per day: 2 squirrels * 30 nuts/day/squirrel = <<2*30=60>>60 nuts/day
Then add the number the sleepy squirrel gathers each day: 60 nuts/day + 20 nuts/day = <<60+20=80>>80 nuts/day
Then multiply the number of nuts gathered daily by the number of days to find the total number of nuts gathered: 80 nuts/day * 40 days = <<80*40=3200>>3200 nuts
#### 3200