Skip to content / Đến nội dung
ThichHocToan.com

MathNet 2009-part-02 — 175 problems (EN–VI) Question 65

Math Olympiad Vault · MathNet 2009-part-02 — 175 problems (EN–VI)

Question 65

At a table there are four people: Luca, Maria, Nicola and Paola. Each of the four either always lies or never lies. Moreover, they do not like to talk about themselves but rather about their friends; so much so that when they are asked who among them always lies, their answers are:

Luca: "every girl always tells the truth"
Maria: "every boy always lies"
Nicola: "there is a girl who always lies, the other always tells the truth"
Paola: "one of the boys always tells the truth, the other never does".

Can you tell how many people at the table always tell the truth?

(A) None
(B) 1
(C) 2
(D) 3
(E) All of them.