Since 1 hour is 60 minutes, 20 minutes is 20/60=1/3 of an hour.
Eating 3 potatoes per 20 minutes is 3/(1/3)=<<3/(1/3)=9>>9 potatoes per hour.
At 9 potatoes per hour, it will take Jason 27/9=3 hours to eat all of the potatoes.
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