My friend told me this complex story. Everyone in it is either a knight, knave, or liar (more than one person can have the same status). Knights always tell truths, liars always lie, and knaves always alternate every statement.
Everyone knew the status of everyone else except for my friend (he knew nothing at first). If anyone lied about what someone said, they didn’t lie about who, when, or whether they said it; they only lied about what the person said. The story goes as follows.
Aaron and Bill were talking to me.
Aaron told me what he was.
At this point, I could tell what Aaron was.
Bill told me one thing that he wasn’t.
Aaron told me that Cassie was a knight.
I then could figure out what Cassie was.
Bill told me that Cassie was a knave.
I thought about this for a minute.
I soon found that the previous thing Bill said allowed me to know for sure what the last of the three people were.
What type is everyone? The puzzle is solvable.
(In reply to
re: Solution by Tristan)
By the rules of the problem, D cannot have lied about who spoke. Both A and B spoke to D. It seems to me that this makes the first statement true, and so D cannot be a liar.
Beyond that, if D were a liar then the actual true statements might be:
A and B were playing golf.
A said his underwear is purple
At this point I could not tell what A was.
B told me he ate lemons for breakfast
A told me he has a pet turtle
I then could not figure out what C was
B told me he likes green beans.
I didn't think about this at all.
I then could not figure anything out.
If this is what really happened then either:
1 - D could not have made the statement
"A and B were talking to me" and be a liar
or, if you allow that
2 - D could be a liar and make all the statements as given, but we would not be able to determine what any of the other three are.
Seems to me that that covers everything. Unless of course you are going to say that the last line "the puzzle is solvable" was also uttered by D, in which case the puzzle may NOT be solvable. But I've been presuming that you, Tristan, a knight, said everything before "A and B were talking to me" and after "what the last of the three people were"
Pretty clever the way the second line of the problem says "Everyone in the story....", and D is in the story. We should have picked up on that. But then again, doesn't it work out if D is a knight? A could have said "I am a liar", B could have said "I am not a knight". Then A would be a knave, B a knave, and C a knight. This is the original solution proposed by others, and I don't see a problem with it if D is a knight....
re(2): Solution
