That probably is too 'practical' question so I will be happy to re-formulate it in more abstract terms if needed.
I have a list of n items (say, 30) and an audience, larger than n (say, 200). I am interested to know what are the most popular three items among this audience. What is the most correct and efficient way of doing it?
I realize of course that there can be the case of a draw, or some other peculiar distribution of preferences that won't allow me to draw any conclusion. But apart of these unlikely situations, if we assume there are top three most preferred items, what could the way to ask the audience the least amount of questions (i.e. efficiency) to these three items with the highest probability (i.e correctness)?