Question : Forty teams play a tournament. Each team plays every other team just once. Each game result in a win for one team. If each team has a 50% chance of winning each game, the probability that at the end of the tournament, every team has won a different number of games is
(A) 1/780
(B) \dfrac{40!}{2^{780}}
(C) \dfrac{40!}{3^{780}}
(D) None of these
Answer : option (B)
solution :
