Crime scene: 162 mystery solving puzzles to find out who the murderer is

Chapter 37 Poisonous Wine and Fine Wine

During the Warring States period, the Qin State implemented the Shang Yang Reform, and the laws were strict.Qin Xiaogong has an aide who is known as the most wise man in the world. If he commits a mistake, he should be executed according to the law.Qin Xiaogong cherishes his talents and wants to save his life, but he can't break Qin's laws.

Therefore, he designed a special execution method, hoping that the wise man could use his wisdom to save his life.On the execution ground stood two warriors, each holding a bottle of wine.Qin Xiaogong told the wise man:
First, the two bottles of wine are indistinguishable in appearance, one bottle is fine wine, the other bottle is poisonous wine.

Second, the two samurai must answer every question, but one only answers the truth and the other only answers the lie, and it is impossible to judge who is telling the truth and who is telling the lie from the outside.

Third, the two warriors know each other's details, that is, they both know who is telling the truth or lying, and who is taking poisoned wine or fine wine.Now the wise man is only allowed to ask any one of the two warriors a question, and then according to the answer he gets, decide which bottle is the good wine and drink it up.

The wise man thought for a while, asked a clever question, and drank the wine.As a result, he was saved from death.If you were wise, how would you formulate the problem and find the wine?
[Answer] A wise man can ask any of the two waiters, let's ask waiter A the following question: "Please tell me, how will waiter B answer the question whether he is holding good wine or poisonous wine?"

If A says that B replied that he was holding poisoned wine, then in fact B must be holding good wine.Because if A tells the truth, then in fact B does answer that he is holding poisoned wine, and because in this case, B is telling a lie, so in fact, B is holding good wine.

If A tells a lie, B actually answers that he is holding fine wine, and because B is telling the truth in this case, B actually holds fine wine.That is to say, no matter which of A and B is telling the truth and who is lying, as long as the wise man gets the answer that B is holding poisoned wine, in fact B must be holding fine wine.

In the same way, if A said that B replied that he had fine wine in his hand, then in fact B must have poisoned wine in his hand.

The cleverness of this question designed by the wise man is that he does not need to know who of the two waiters is telling the truth and who is telling the lie, so he can be sure that the answer he gets must be a false answer.Because if A tells the truth and B tells a lie, the situation is that A tells a lie to a wise man truthfully, and what the wise man hears is a lie: if A tells a lie and B tells the truth, then A tells a lie The truth turns into a lie and told to the wise, but what the wise hear is still a lie.In short, what the wise man hears is always a lie.

(End of this chapter)