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One Native, Two Roads (Posted on 2006-05-22) Difficulty: 3 of 5
You are lost once again in the land of Knights, Knaves, and Liars, and once again you find yourself at a fork in the road. You know that one path will lead you to a safe return home, while the other will lead you to your own gruesome demise. (You really need to find a better vacation spot next year!)

Standing at the fork is a native, who might be either a Knight (who always tells the truth), a Knave (who alternates between true and false statements), or a Liar (who always lies). You have no way of knowing which he is. Worse yet, you realize that if he is a knave, you don't know if he will tell you the truth first, and then lie, or lie first and then tell the truth, etc.

What is the fewest number of questions you have to ask to find out which is the safe road, and what are they?

See The Solution Submitted by tomarken    
Rating: 3.8333 (6 votes)

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Solution 3 Questions | Comment 17 of 21 |

1) Are you a knave?

2) Are you a knave?

Knight answers no, no

Liar answers yes, yes

Knave answers yes, no or no, yes

3) Which road do I take to safety?

 

Listen to the no, no responder.  Take the opposite of the yes, yes responder.  If it was the yes, no or no, yes responder,  follow the advice if the response to the first question was yes and take the opposite road if the response was no to question #1.


  Posted by Dax Fuiten on 2006-05-29 00:11:03
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