181.The Drunk Passenger
★★★conditional probabilityIMC Trading
One hundred passengers board a full flight. The first passenger ignores their assigned seat and sits in a uniformly random one. Every later passenger takes their own seat if it is free, and otherwise picks a free seat uniformly at random. What is the probability that the last passenger gets their own assigned seat?
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Only two seats can possibly be left for the last passenger. Ask which of them is more likely to survive.
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