Hi,

I'm doing my assignment, I'm stuck in between.

I'm summarising what is need.

in a flight there are 100 seats, 1st person lost his boarding pass and do not know his seat number so he sit randomly, then 2 to 99 persons enter the flight and they keep shifting the first guy (if he is seated in their seat). Finally when 100th person enter what is the average times the 1st person is shifted?

So my question is, how to find the average using probability?

Thanks in advance!