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2015 AMC 12B Question 9

AMC12 · 2015 AMC 12B

Question 9

Larry and Julius are playing a game, taking turns throwing a ball at a bottle sitting on a ledge. Larry throws first. The winner is the first person to knock the bottle off the ledge. At each turn the probability that a player knocks the bottle off the ledge is $\dfrac12,$ independently of what has happened before. What is the probability that Larry wins the game?
  1. $\dfrac12$
  2. $\dfrac35$
  3. $\dfrac23$
  4. $\dfrac34$
  5. $\dfrac45$