Imagine there are a 230 people in line to board a plane that seats 230. The firs
ID: 3261752 • Letter: I
Question
Imagine there are a 230 people in line to board a plane that seats 230. The first person in line realizes he lost his boarding pass so when he boards he decides to take a random seat instead. Every person that boards the plane after him will either take their "proper" seat, or if that seat is taken, a random seat instead. Question: What is the probability that the last person that boards will end up in his/her proper seat.
A) 1/230
B) .80
C) .10
D) 2/230
E) .50
F) .90
G) .40
H) .20
I) none of these
Explanation / Answer
This is a very famous problem.
the answer is 0.5.
why ?
because for the last person the seat that remains empty can be his original seat or not.
the pervious passengers, what they do will not matter. so, for the last person there are two possible outcomes. one is favorable. so the probability is 1/2