Problem #PRU-103883

Problemas Matemáticas discretas Teoría de conjuntos y lógica Lógica matemática Lógica matemática (otros)

Problem

A space traveller decided to visit the planet and upon arrival he met three inhabitants. The traveller asked each of the inhabitants: “How many truth tellers are there among your companions?”. The first one answered: “None.” The second one said: “One”. What did the third alien say?