You have a fox, a chicken and a sack of grain. You must cross a river with only one of them at a time. If you leave the fox with the chicken he will eat it; if you leave the chicken with the grain he will eat it. How can you get all three across safely?
Take the chicken over first. Go back and bring the grain next, but instead of leaving the chicken with the grain, come back with the chicken. Leave the chicken on the first side and take the fox with you. Leave it on the other side with the grain. Finally, go back over and get the chicken and bring it over.
A six-digit number represented by ABCDEF (each letter represents a different number) can be multiplied by 2, 3, 4, 5, and 6 and yet no new digits appear in the result. As a matter of fact, all the digits are rotated. What is the number?
Ronald has a rare opportunity to meet the President of the United States. During his visit the president gives him a gift but tells Ronald he is never to sell it unless he sees the president again. Ronald consents, but the president dies later that year. Years later a man offers to buy the President’s gift for $1000. Ronald agrees and exchanges the gift for 20 crisp $50 bills. Did he keep his promise?
Yes. The president was Ulysses S. Grant, who died in 1885 and whose face has been on the $50 bill since 1913. He saw the president on the bills before he made the exchange.
Daughter-in-law. Her daughter’s father is her husband (she’s only been married once and is devoted, meaning she didn’t have an affair). This means John’s son is her husband, so John is her father-in-law, making her the daughter-in-law.
A penguin. If all four walls face north the house must be at the southernmost point of the earth. Really, any native antarctic bird would work.
This brain teaser is quite similar to the guy whose house walls face south and sees a bear, then you’re asked the color of the bear. The bear would be white (a polar bear) as they’re the only bears indigenous to the north pole. A lawyer would claim it’s all circumstantial evidence and the bear could be an imported brown bear. The lawyer makes a valid point.