How many feet are in a yard?

Dad and Duck were talking to each other when Dad asks Duck, "Do you know how many feet are in a yard?" She ponders a minute and looks to me for some guidance. She has a look on her face that she should know this answer, but where is it when she needs it. Hummmmm, do I tell Dad I don't know or do I just give an answer?  Reluctantly she answers 3? Dad says no. Then she looks at me with a more puzzled look. Dad answers, "It depends on how many people are standing in it."
Hope you laughed as much as we did.