Once, a king wanted to find a wise man to be his Prime Minister.
So according to a plan, he made a riddle. "A man has a boat to cross the river. Only two can go in the boat at one time. The man has to take a lion, a goat and a bundle of grass to the other bank so that in a way no one will eat the other. What will he do?"
No one in the kingdom could give the answer. Then a young man went to the king and said, "Your Majesty, the man will take the goat to the other bank. Then he will go to get the lion. He will bring the lion to the other bank and take back the goat with him. Then he will take the grass to the lion because lion won't eat the grass. He will row back to get the goat to the other bank."
The king was amazed by his cleverness because he had never let the grass and the goat or the lion and the goat to be together.
So the king was sure of his intelligence and appointed him as the Prime Minister.