Knights always tell the truth,liars always lie,and knaves alternate between truths and lies.

Two people named Jimmy and Johnny make the following claims.

Jimmy:I am a knave.
Johnny:Jimmy is not a knight.
Jimmy:Johnny is a knave.
Johnny:Jimmy is a knave.

What are each?

(In reply to Solution by Lewis)

It's possible to slightly shorten Lewis's logic as follows:

Jimmy says 'I am a knave', so he is either a knave telling the truth or a liar - in either instance his second statement must be false, therefore Johnny is either a knight or a liar.

Johnny says 'Jimmy is not a knight' which is true, therefore Johnny must be a knight. Johnny the knight also says 'Jimmy is a knave' which must also be true.

So we have Johnny is a knight and Jimmy is a knave.

Posted by fwaff on 2003-07-07 06:32:25