Lizzy: If it takes 20 minutes to paint a house, how many houses can you paint in 3 hours?.
Me: Hmmm, let me think. I think this is the detailed solution:
User
There are 3 hours * 60 minutes / hour = 180 minutes in 3 hours. You can paint 180 minutes / 20 houses / minute = 9 houses in 3 hours. Final answer: 9.
Assistant