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 truth-teller.
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(5): solution
by Ady TZIDON)
Well, if you insist, all we need to know is in the statement:
"I get six distinct answers and deduce the true one."
In other words, there are 6 answers, 1 of which is true. So 5 are untrue. So there are 5 liars.
In fact, we don't even need to know what the question was.