Tue
Feb
2
Tuesday Teaser #11
Consider three types of people in a medieval kingdom - Knights, Knaves, and Normals. Knights always tell the truth, Knaves always lie, and Normals can do either. The King wants his daughter to marry a nice normal Normal, not one of those goody-goody Knights or devious scoundrel Knaves.
- How can you make a true statement that will convince the King you are a Normal?
- How can you make a false statement that will convince the King you are a Normal?
- How can you make a statement that will convince the King you are a Normal, but he won’t know whether it’s true or false?
For a (much) harder twist, suppose the King doesn’t trust those unpredictable Normals and wants his daughter to marry a Knight or a Knave instead.
- How can you, in one statement, convince the King you are a Knight?
- How can you, in one statement, convince the King you are a Knave?
- How can you, in one statement, convince the King you are not a Normal, but leave him unable to deduce whether you are a Knight or a Knave?
This puzzle can be found in it’s original form in Raymond Smullyan’s What is the Name of This Book? although this slightly modified version is taken from the excellent [wu:riddles].
