You have 3 people with you. You know that one always tells the truth, and one always tells lies, and the other one strictly alternates telling lies and truths.
You are going to serve dinner, but ask who likes strawberries, and who doesn't. Their answers are as follows:
A: C never has told a lie.
I like strawberries.
B: A has never told the truth
I don't like strawberries
C: I always lie.
I don't like strawberries.
Who likes strawberries, and who doesn't?
(In reply to Answer
by K Sengupta)
If C's first statement is true, then as the liar C is speaking truthfully in that statement. This is a contradiction. Thus, C's first statement is false. Since A's first statement asserts that C is the truthteller, that statement must be false too. Accordingly, each of A and C has made at least one false statement, so that neither can be the truthteller. Thus, by the given conditions, it follows that B is the truthteller, so that both his statements must be true.
Accordingly, from B's truthful statements, it follows that A is the liar and B does not like strawberries.
Since A is the liar and B is the truthteller, it follows that the remaining person (C) must be the alternator. From A's falsely stated second statement, it follows that A does not like stawberries. Since C is the alternator, with his first statement being false, it follows that his second statement must be true, so that C does not like strawberries.
None of A, B and C likes strawberries.
B is the truthletter, C is the alternater and A is the liar.