1. The problem statement, all variables and given/known data Z plays a game where independent flips of a coin are recorded until two heads in succession are encountered. Z wins if 2 heads in succession occurs. Z loses if after 5 flips, we have not encounter two heads in succession. 1) What is the probability that Z wins the game? 2) Suppose coin is fair. Z plays twice. What is the probability that both games have the same outcome? 2. Relevant equations N.A. 3. The attempt at a solution I get very confused by questions related to probability. :( There are 5 flips at most so the sample space has 2^5 = 32 possible outcomes. When seen as 5 "slots", as long as two adjacent slots are filled with H (for "heads") then Z wins. P(Z wins) = 1 - P(Z loses) Let X = number of heads. Then, Z loses when X = 1. Z loses in some cases when X = 2,3. X = 1 : There are 5 possible outcomes. X = 2 : The two heads are either 1 slot apart (3 choose 1 = 3 outcomes) or 2 slots apart (2 choose 1 = 2 outcomes) or 3 slots apart (1 outcome) X = 3 : The three heads need to be in slot 1,3,5 => 1 outcome. So total outcome that results in a loss = 1 + 5 + 3 + 2 + 1 = 12. Therefore, P(Z win) = 1 - 12/32 = 20/32 = 5/8. Question : Is this method correct? Are there "cleaner" methods? I have no idea how to start part 2.