20CS110001  Introduction to Computer Science  Fall 2010 

Double Doors II Puzzle
You are in front of the same two doors (one door leads to incredible
wealth and the other leads to nothing of value but you do not know
which is which). There are three other people (who do know which is
which) standing in front of the doors. One always tells the truth and
one always lies. The third person is unpredictable  telling the truth
or lying randomly. Of course, you have no idea which person is which.
You can ask two Yes/No questions (one at a time to only one person each) in order to find the riches. What questions do you ask, and to whom, to find the riches? 

solution 