An elevator starts at the basement with 9 people (excluding the elevator operator) and discharges them all by the time it reaches the top floor, which is floor number 6. In now many ways could the operator have perceived the people leaving the elevator if all the people look the same? (there are totally 6 floors excluding the basement)
2002
This is a question based on distributing similar things to different groups (SàD)
i.e. the distribution of 9 similar things to 6 different groups
A+B+C+D+E+F=9
Solving, we get 14C5= 2002.