Five knights stand in a circle facing inward. Each knight can only see the knight directly across from them. Knight A looks at Knight C. Knight B looks at Knight D. Knight C looks at Knight E. Knight D looks at Knight A. Knight E looks at Knight B. If every knight tells a lie when looking at someone wearing red, and the truth otherwise, and exactly two knights are wearing red, who are they?
Knights A and C
Let's trace the lines of sight: A sees C, B sees D, C sees E, D sees A, E sees B. If A and C are wearing red, then C (seen by A) and A (seen by D) are wearing red. This means A and D lie (since they look at red), while B, C, and E tell the truth. Checking consistency: C looks at E (not red, tells truth). D looks at A (red, lies). E looks at B (not red, tells truth). A looks at C (red, lies). B looks at D (not red, tells truth). The conditions hold perfectly.
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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