MathDB
TOT 1998 Spring AJ4 always tell the truth or always lie, on a circle

Source:

May 11, 2020
combinatoricsgamegame strategy

Problem Statement

A traveller visited a village whose inhabitants either always tell the truth or always lie. The villagers stood in a circle facing the centre of the circle, and each villager announced whether the person standing to his right is a truth-teller. On the basis of this information, the traveller was able to determine what fraction of the villagers were liars. What was this fraction?
(B, Frenkin)