In a small village there are two kinds of people: liars and truthtellers.
Everybody knows everybody and everybody knows as well who is a liar and who’s a truthteller.
I approach six villagers and pose the same question to each of them:
"How many liars are among you?"
I get six distinct answers (integers, of course) and deduce the true one.
How many liars are in that group?
Liars always lie and truthtellers never do.
(In reply to
re(3): solution by Ady TZIDON)
What if the answers were 1, 7,13,55,66,144?
Wouldn't you agree that there are six liars?
I guess so; ok, but What if the answers were 1, 2, 3, 4, 5 and 6?
Wouldn't you agree that there were five liars, which you could also deduce?
If that is the case, then we as puzzle solvers can't determine the number of liars in the group: either 5 or 6.

Posted by Charlie
on 20151115 18:39:50 