I'm studying Probability and can't solve this question:
Random tournaments: consider a sport tournament in which n teams participate. Each team plays one match against each other team. Each such match ends with one of the two teams winning (there are no draws). Assume that all teams are equally strong, so each match has a random winner. We say that a team is the clear winner of the tournament if it won all its n − 1 matches (this team beats all other teams). What is the probability that the tournament ends without a clear winner for n = 10?