500
In the World Series, two teams, A and B, play each other until one team has won 4 games. For example the "word" ABBAAA represents a 6-game series in which team A wins games 1, 4, 5, and 6. What is the number of possible different 6-game series won by team A?
10 - draw a possibility tree for a 6 game series and only count the ones where A wins