The following two facts are known about Adam, Bert, and Carl:

1) Of Adam, Bert, and Carl, there is one knight, one knave, and one liar.
2) Adam said once, "Bert said that Carl isn't a knight."

Can you ask one yes/no question to one person and figure out who is who? If not, how many questions must you ask?

Dear Adam: Were you being a lying knave when you quoted Bert?

The answer gives you three test points for Adam:

1) Did he quote bert?

2) was he a knave?

3) was he lying?

Adam's answer implies an answer to each of these questions, which can then perhaps be combined to derive the solution. But I'm feeling lazy so I'll let someone else prove (or disprove) me.

Posted by Ben Gornall on 2005-02-17 05:29:19