Q: It takes David 10 minutes to wash 4 windows. David's house has 64 windows. How many minutes will it take David to wash all of the windows?
A: 160
Explain how we arrive at this answer:
Explanation: It takes 10 minutes to wash 4 windows and he has 64 windows so that breaks down to 64 / 4 = 16 units. It takes 10 minutes to wash a unit of windows and he has 16 units so 10 * 16 = 160 minutes.