MATH STINGER #71 
by Dr. Joel C. Fowler 
Assistant Professor of Mathematics 

 Suppose that two teams, say the Braves and Indians, are playing a best of 5 series of games. 
Assume that the probability that the Braves win each game is a fixed number p. A bookmaker remarks 
that in his opinion the probability that the Braves win the series in 3 games is the same as the probability 
that the Braves win the series in 5 games. Assuming that the bookmaker is correct, find the exact value of p 
(not a decimal approximation). A more difficult puzzle, requiring the techniques of a basic probability course, 
is the following. Suppose that in a best of 7 series one bookmaker says the probability that the Braves will 
win in 7 is the same as the probability that the Indians will win in 6. Another bookmaker says the reverse. 
That is, the probability that the Braves will win in 6 is the same as the probability that the Indians will win in 7. 
Which bookie would you say favors the Braves more? For each bookie find p, the probability that the Braves 
win each game, to justify your answer.

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