Disclaimer: I am not looking for a solution to this, just a clue to help me arrive by myself to the right solution.
Two players are rolling a die, and the first one to get three ones, wins. So far, player A has gotten two ones, and player B has gotten one. What is the probability that player A wins?
What I am struggling with is the fact that the game can go on forever, so I am not sure of how to approach the problem. Any guidance is greatly appreciated.