###Human: There is a lot of dust in Susie's house. It takes her 2 hours to vacuum the whole house. She can vacuum each room in 20 minutes. How many rooms does she have in her house?, ### Assistant: Susie spends 2*60 = 120 minutes vacuuming.
Since she can vacuum each room in 20 minutes, she has 120/20 = 6 rooms in her house. 
 So the answer is :  6