1. The problem statement, all variables and given/known data A fair coin is continually flipped. What is the probability that the pattern T,H occurs before the pattern H,H, where T and H respectively denote Tail and Head of a coin? 2. Relevant equations Prob. = (n r) (pr)(1-p)n-r 3. The attempt at a solution I am thinking whether the question asks about: i. prob. of TH vs HT vs TT vs HH ii. THHHHHHH...or TTHHHHHH... or HTHHHHHH... or HTTHHHHH... or HTTTTTHHH... or .... If it is the 2nd one, how can we calculate the prob.? It looks like an infinitely long series... or should I let there be n trials? Then I use binomial distribution to find?