This one is quite old, I'm posting it because I've enjoyed it immensely and want to share to those who might not have seen it yet, and to
see if anyone would present new and innovative solutions.
Here we go:
A long time ago a cruel tyrant ruled over a kingdom. One day the tyrant king heard rumors of the development of a new deadly poison in his kingdom. The rumors say that this poison comes in different potencies, the stronger ones can kill in mere minutes while the weaker ones may take some more time to take effect. Apparently the only antidote to this poison is a more potent version of itself.
Fearing that his enemies may use it against him, the king figured that he should have a vial of the most potent blend of the poison with him in case he needs it to counteract a weaker one he may ingest unwillingly. To accomplish this he called upon his two best assistants; the wizard and the witch. He gave both a week to each brew the strongest version of the poison they can; after a week they were to come back and let the king test who made the stronger poison.
The test is as follows:
The wizard and witch drinks the other's poison; then they drink their own. The person who does not die would be the one who had made the stronger poison and thus wins.
After hearing what the test was gonna be, the wizard was uneasy for he knew that the witch knows more about poisons than him and can unquestionably brew a stronger poison. With this in his mind he thought of a plan where he can guarantee his survival even if the witch's poison is superior.
The witch however is also smart, she knew the wizard knew he could never beat her and thus would resort to cheating. With this in mind the witch thought of how the wizard would cheat and thought of a counter.
A week passed and the king summoned the wizard and witch once more. They exchanged bottles and drank; they exchanged again and drank. After a few minutes, the wizard dropped dead.
Q> What was the wizard's trick? What was the witch's counter-trick?