You walk into a room and see a bed. On the bed there are two dogs, four cats, a giraffe, five cows and a duck. There are also three chickens flying above the bed. How many legs are on the floor?
Since all of the animals are on the bed and no other furniture is mentioned in the room, there are six legs on the floor. Four legs from the bed and your own two legs as you stand in the room, amazed that someone managed to get so many animals onto a bed. And the ceiling must be vaulted to fit a giraffe. Also, who’s on cleanup duty?
Fred was almost done packing for the day, with five packages left. Unfortunately, Fred dropped the labels and had no idea which label went to which package. What is the probability that Fred managed to correctly label exactly four of the five packages?
Zero. If Fred had correctly labeled four packages, the fifth label would belong to the fifth package and all packages would be correctly labeled. Therefore it is impossible to mislabel exactly four packages.
I never was, am always to be. No one ever saw me, nor ever will. And yet I am the confidence of all, To live and breathe on this terrestrial ball. What am I?