Possibilities for Tournament Play
Teams A and B are to play each other repeatedly until one wins two games in a row or a total of three games. One way in which this tournament can be played is for A to win the
first game, B to win the second, and A to win the third and fourth games. Denote this by
writing A–B–A–A.
a. How many ways can the tournament be played?
b. Assuming that all the ways of playing the tournament are equally likely, what is the
probability that five games are needed to determine the tournament winner?