A farmer with 11 cows likes to milk them in a different order each morning. How many days can he do this without repeating?
I believe that it's 11!, but don't fully take my word for it.
11! days = 11! = 39916800 days
That is about 109,000 years.
So since cows, or people do not live that long he can essentially have a different order for every day.
