Question 10
Xavier,Ylenia and Zoe want to reveal whether someone won the lottery while keeping the winner’s identity secret. Each pair meets and tosses one coin. Each person announces whether the two tosses they participated in were the same or different. Everyone tells the truth except a winner, who gives the opposite answer. In this example Zoe won and all announce “different”; Úp and Ngửa label the two coin faces.
Now Xavier says “same”, Ylenia says “same”, and Zoe says “different”. At most one person won. Who is the winner?
Now Xavier says “same”, Ylenia says “same”, and Zoe says “different”. At most one person won. Who is the winner?