A Astrologer's Prediction

The ministers became resentful after hearing the truthful predictions of the astrologer.

They told the king many fabricated stories about the astrologer.

Believing them, the king came up with a trick to have the astrologer executed.

The king asked the astrologer, "You must make a prediction to prove whether you are a fake astrologer or not. When will you die?"

The astrologer was immediately shocked! If he gave a specific day, the king would kill him before that day, proving the prediction wrong.

If he said he would die soon, the king would kill him later, again proving the prediction wrong. In either case, the king would declare his prophecy false and have him killed.

However, the clever astrologer made a prediction. The king admitted defeat and let him go.

Question: What was that day?

Answer: The day before the king's death. The king was afraid that if he killed the astrologer, the very next day the prediction would come true, and he would die.