How long do you have to wait ?

Have you ever wondered ?

1.If you saw a falling star after x minutes how long must you wait to be 90% sure of seeing another one?

2.If you found a pearl in an oyster after opening x oysters how many must you open to see another one ?

Enter first wait or number of trials:
You will have to wait x minutes or go through x samples :
to be 90% sure of finding another .