Originally Posted by

**satzer** Hello,

I would appreciate some help on how to get started on this problem.

Consider a 45-story building. Person A lives on the 20th floor. Let's say 5 people (including person A) entered an elevator and the elevator is going up and everyone pressed a different floor (button), what is the probabiltiy that person A was the 1st one to exit the elevator? The 2nd? The 3rd? The 4th? The 5th (i.e., the last)?

I know that if the building had only 20 floors then the probability of person A exiting the elevator last would be 1.

Also if there are only 2 people, then is the probability of person A leaving 1st 20/45 ?