Step-by-step explanation:
This is a classic puzzle!
The answer is that the probability that the last person ends in up in his proper seat is exactly
1
2
The reasoning goes as follows:
First observe that the fate of the last person is determined the moment either the first or the last seat is selected! This is because the last person will either get the first seat or the last seat. Any other seat will necessarily be taken by the time the last guy gets to 'choose'.
Since at each choice step, the first or last is equally probable to be taken, the last person will get either the first or last with equal probability:
1
2
.
Sorry, no clue about a physical system
