Five knights stand in a row facing East. Each wears either a red cloak or a blue cloak. Sir Arthur, looking straight ahead, sees four knights. He states: 'I see at least one red cloak and at least one blue cloak ahead of me.' Sir Brian, standing directly behind Arthur, hears this and says: 'I see four cloaks ahead of me, but I cannot tell their exact colors.' What color is Sir Arthur's cloak?
Red
If Arthur wore blue, Brian would see four blue cloaks ahead of him and know their color immediately. Since Brian cannot tell their colors, the group ahead of him must contain a mix of red and blue. Furthermore, for Arthur to honestly see at least one of each color ahead of him while standing second in line, his own cloak must be red to allow for the mix visible from his position.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Hard. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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