You walk up to a mountain that has two paths. One leads to the other side of the mountain, and the other will get you lost forever. Two twins know the path that leads to the other side. You can ask them only one question. Except! One lies and one tells the truth, and you don't know which is which. So, What do you ask?
You ask each twin "What would your brother say?"
This works because.... Well let's say the correct path is on the left side. So say you asked the liar "What would your brother say?" Well, the liar would know his brother was honest and he would say the left side, but since the liar lies, he would say right. If you asked the honest twin the same question, he would say right, because he knows his brother will lie. Therefore, you would know that the correct path was the left.
A king has no sons, no daughters, and no queen. For this reason he must decide who will take the throne after he dies. To do this he decides that he will give all of the children of the kingdom a single seed. Whichever child has the largest, most beautiful plant will earn the throne; this being a metaphor for the kingdom.
At the end of the contest all of the children came to the palace with their enormous and beautiful plants in hand. After he looks at all of the children's pots, he finally decides that the little girl with an empty pot will be the next Queen. Why did he choose this little girl over all of the other children with their beautiful plants?
The king gave them all fake seeds and the little girl was the only honest child who didn't switch seeds.
A wealthy man lives alone in a small cottage. Being partially handicapped, he had everything delivered to his cottage. The mailman was delivering a letter one Thursday when he noticed that the front door was ajar. Through the opening he could see the man's body lying in a pool of dried blood. When a police officer arrived he surveyed the scene. On the porch were two bottles of warm milk, Monday's newspaper, a catalog, flyers, and unopened mail. The police officer suspects it was foul play. Who does he suspect and why?
The police officer suspects the newspaper delivery person. The absence of Tuesday's and Wednesday's newspaper indicates that the delivery person knew there was no one there to read it.