The farmer had all the answers about the cows.
Interviewer: How much milk do these cows give?
Farmer: Which one? The black one or the brown one?
Interviewer: Brown one.
Farmer: A couple of litres per day.
Interviewer: And the black one?
Farmer: A couple of litres per day.
Interviewer (naturally a bit flummoxed): I see. What do you give them to eat?
Farmer: Which one? Black or brown?
Interviewer: Black.
Farmer: It eats grass.
Interviewer: And the other one?
Farmer: Grass.
Interviewer (now annoyed): Why do you keep asking which one when the answers are the same?!
Farmer: Because the black one’s mine.
Interviewer: Oh, and the brown one?
Farmer: It’s also mine.