###Human: 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?, ### Assistant: 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 
 So the answer is :  160