Date: Aug 12, 2012 11:56 AM
Author: Angela Richardson
Subject: (no subject)

If a coin is flipped until there has been at least one head and at least one tail and gcd(number of heads,number of tails) >1, what is the expected number of flips? 

I simulated 1000000 games because I couldn't be bothered to think and got a mean of 6.00584, and if the answer is 6 there ought to be some elegant proof that is eluding me.