Problem #PRU-60921

Problemas Matemáticas Discretas Teoría de Conjuntos y Lógica Lógica Matemática Lógica Matemática (otros)

Problem

There are 4 coins. Of the four coins, one is fake (it differs in weight from the real ones, but it is not known if it is heavier or lighter). Find the fake coin using two weighings on scales without weights.