Difficult Question:

This type of question has nothing to do with your career. Right or wrong answers do not matter. Interviewers want to see if you can manage with non-related subjects, and think on your feet. They might be testing your ability to reason, problem solve, and utilize resources.
I am not sure but my guess would be at least two players on each side, one in the goal and one to play defense. I will put the number between seven and twelve on each team. I would definitely want to consult a colleague of mine who plays soccer if this was a game show right now using phone a friend is important sometimes in utilizing available resources.