Question : There are hundred prisoners in a jail. The jailor is benign and decides to give them a chance to be free. Here is what he is going to do: make all the prisoners stand in a row so that a prisoner can see only those prisoners who are in front of him. Then make them wear a cap. The cap can be either white or black. Then ask the last man the color of his cap. Then the second last and so on. When all have answered, let go those who have answered correctly. Before starting this exercise, he gives all of them to discuss and come up with some strategy. Does a good strategy really exist? If yes, what is it? and using that strategy, how many of them we be freed?
Answer : Sorry guys, I don’t know the solution. If you know it, post as comment here. I can update here.