Elevator, 24 people, 8 floors: prob. of stopping on floor 7 w/o you pushing button

[ojhanaresh]

There is a lift carrying 24 persons and you are one of them. There are total 8 floors in the building. You want to get down at the 7 th Floor. What is the probability that the lift will stop at 7 th Floor without you pressing any lift buttons?

 

[stapel]

There is a lift carrying 24 persons and you are one of them. There are total 8 floors in the building. You want to get down at the 7 th Floor. What is the probability that the lift will stop at 7 th Floor without you pressing any lift buttons?

What are your thoughts? What have you tried? How far have you gotten? Where are you stuck?

Please be complete. Thank you!