perplexus.info :: Liars and Knights : No honor among thieves

No honor among thieves (Posted on 2006-01-08)

Two thieves have being working together for years. Nobody knows their identities, but one is known to be a Liar and the other a Knave. The local sheriff gets a tip that the bandits are about to commit another crime. When the sheriff arrives at the seen of the crime, he finds three men, A, B, and C. C has been stabbed with a dagger. He cries out, “A stabbed me” before anybody can say anything else; then, he falls down dead from the stabbing.

Not sure which of the three men are the crooks, the sheriff takes the two suspects to the jail and interrogates them. He gets the following information.

A’s statements:
1. B is one of the crooks.
2. B’s second statement is true.
3. C was telling the truth.

B’s statements:
1. A killed the other guy.
2. C was killed by one of the thieves.
3. C’s next statement would have been a lie.

C’s statement:
1. A stabbed me.

The sheriff knows that the murderer is among these three people. Who should the sheriff arrest for killing C?

Submitted by fractaloon

Rating: 3.3333 (3 votes)

Solution: (Hide)

A's third statement must be a lie. If not, then A, B, and C each have one true statement. Since at least one person is a known liar, that can't be true.

If his 3rd statement is a lie, he is a liar or a knave and his first statement must be a lie.

Therefore, the thieves are A and C.

Since B's 1st statement is a lie, his third must also be a lie. Therefore, C was a Knave.

If C was a Knave, then the other thief, A, is a Liar. That means B's second statement is true.

B killed C.

Comments: ( You must be logged in to post comments.)

Subject	Author	Date
Sol	Andre	2010-05-28 19:20:49
answer	K Sengupta	2007-06-30 10:04:20
re: can't arrest dead men	lance	2006-03-23 08:17:08
Same answer here	Mike	2006-03-03 17:48:22
answer	matthew bordas	2006-02-24 13:39:57
No Subject	kelly murray	2006-02-14 21:57:55
re: Solution	bunkr	2006-02-01 14:42:26
re: Solution	bunkr	2006-02-01 14:26:12
can't arrest dead men	mickey	2006-01-29 13:18:57
Solution	Paddy	2006-01-09 08:16:17
Solution	Robby Goetschalckx	2006-01-09 05:36:47
No Subject	Eric	2006-01-08 12:12:47

Please log in:

Login:
Password:
Remember me:

Sign up! \| Forgot password

Search:

Search body:

Forums (1)
Newest Problems
Random Problem
FAQ | About This Site
Site Statistics
New Comments (6)
Unsolved Problems
Top Rated Problems
This month's top
Most Commented On

Chatterbox:


perplexus dot info