All about flooble | fun stuff | Get a free chatterbox | Free JavaScript | Avatars    
perplexus dot info

Home > General > Cryptography
I don't know. (Posted on 2006-02-16) Difficulty: 2 of 5
ou are a logician in training for the police, and the time has come to take the certification test. The police chief brings you the test one morning, and says, "I must warn you, this is your only chance at the certification test; If you fail, you must keep training for another year before you can take it again."
           
- Five suspects were interrogated for a bank robbery.
             
- Each suspect was either a knight, a knave, or a liar.
         
- Knights always tell the truth.
       
- Liars always lie.
       
- Knaves strictly alternate truths and lies with each statement.
                   
- Police have evidence that suggests the perpetrator acted alone.
                   
- Police have evidence that suggests the perpetrator acted alone.

>During the interrogation, two questions were asked (consecutively) of each of the five suspects. Each suspect heard the other suspects' responses, and none of them made a statement between his or her two answers. Here are the two questions and their responses.

"Did you rob the bank?"
A: No.
B: No.
C: No.
D: Yes.
E: Yes.

"Who robbed the bank?"
A: E.
B: A.
C: l don't know.
D: E.
E: A.

The interrogators mentioned that something about their statements didn't seem quite right. The police chief adds, "The only hints I can give you are that C is not a knight and that there is only one correct answer. I'll be back in 24 hours to ask you who robbed the bank."

No Solution Yet Submitted by Dustin    
Rating: 3.3333 (6 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
re(3): Solution using correct version of the puzzle | Comment 49 of 52 |
(In reply to re(2): Solution using correct version of the puzzle by Avin)

Avin: I found the missing "knights" yesterday, but as I lamented in the chatterbox, I didn't know where to go from there.  You have a good idea with the knights > l(iars), I wasn't sure how it all fit together.  I'll take your word for it that only one possibilty exists with more knights than liars (I'm too tired now to go back and look!)

Dustin: I feel sorry that the orinigal puzzle text was wrong - you were right, having to post the correction as a comment really did give it away, it would have been a much more satisfying find if it had been right all along...still a lot of fun though!

Now, the question remains...is Avin right?  Or is there more??  I'm almost saddened to see this one nearing the end, I've been losing sleep over it for like two weeks now. :)


  Posted by tomarken on 2006-03-08 22:15:23
Please log in:
Login:
Password:
Remember me:
Sign up! | Forgot password


Search:
Search body:
Forums (0)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (9)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:
Copyright © 2002 - 2017 by Animus Pactum Consulting. All rights reserved. Privacy Information