Take the 2-minute tour ×  Possible Duplicate: Taking Seats on a
Plane  The 120 seats on a Northeast Airlines flight were
completely booked, with each of the 120 passengers having
different assigned seats. The passengers entered the plane one-
by-one. Unfortunately, the first passenger couldn’t read their
boarding pass and sat in a (uniformly) random seat. Each
subsequent passenger sat in their assigned seat if it was
available when they entered and sat in a (uniformly) random
empty seat otherwise. What is the probability that the last
passenger sat in their assigned seat?  My intuition says this is
1/2, but I don't know how to go about this formally.
share|improve this question  marked as duplicate by Aryabhata,
Did, Henry, Matt N., Martin Sleziak Jan 25 '12 at 8:14   The
usual intuition about this problem is to think that the answer
must depend on the number $n$ of passengers/seats (and oddly,
people often suggest that the probability is $\frac1n$...).
Curious to know how your intuition leads you to the answ