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?
Jimmy's saying he's a knave classifies him as either a knave or liar.
Johnny's saying Jimmy's not a knight challifies him as being truthful, therefore a knight.
Jimmy's saying Johnny's a knave is a lie; he still could be a knave or liar.
Johnny's identifying Jimmy as a knave clarifies which Jimmy is.
Jimmy is a knave; Johnny is a knight.
Solution
