Problem of the Week 849

Alice Rozencrantz and Bob Guildenstern

Alice tosses 849 fair coins and Bob tosses 850. What is the probability that Alice gets more heads than Bob?

Source: Five Hundred Mathematical Challenges, by Barbeau, Klamkin, and Moser, MAA, 1997.

© Copyright 1997 Stan Wagon. Reproduced with permission.

The Math Forum

2 October 1998