Three people are standing on some stairs. They are each wearing a hat. They are only allowed to face forwards, so they cannot see the color of their own hat, only the color of the hat of the one or two people in front of them (depending in which position they are). The hats they are wearing have been chosen from a pile of two red hats and two blue hats. All three men will be shot in one minute unless one of them shouts out (correctly!) the colour of their own hat. Who shouts out and how do they know the color of their hat? (Work out the answer for the most difficult situation!)
Could somebody please refine these rules for me?
Can they talk amongst themselves?
Does only one have to shout out the correct color to save them all?