Your back. You have one and it’s easy to touch but hard to look it. A common phrase is to “watch your back” and it’s common to “have your friend’s back.” When apologizing, you often want to take back what you said. You can throw out your back, but you can’t throw it away. And back pain causes people pain every day.
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?
Two scruffy dogs were walking down the street. The first dog turned to the other and said, “Do you realize that if one of your fleas jumped onto me we would have the same number of fleas?” The second replied, “Yes, but if one of your fleas jumped onto me I would have five times as many fleas as you.” How many fleas are on each dog to begin with?
As a result of temporary magical powers, you have made it to the Wimbledon finals and are playing Roger Federer for all the marbles. However, your powers cannot last the whole match. What score do you want it to be when they disappear, to maximize your chances of hanging on for a win?
It sounds obvious that you should ask to be ahead two sets to love (it takes 3 out of 5 sets to win the men’s), and in the third set, ahead 5-0 in games and 40-love in the sixth game. (Probably you want to be serving, but if your serve is like mine, you might prefer Roger to be serving the sixth game down 0-40 so that you can pray for a double fault.)
Not so fast! These solutions give you essentially 3 chances to get lucky and win, but you can get six chances—with three services by you and three by Roger. You still want to be up two sets to none, but let the game score be 6-6 in the third set and 6-0—in your favor, of course—in the tiebreaker.
The trick is that the word “dead” represents a number in hexadecimal. That number in base 10 is 57005, and adding one more to include yourself gives you: 57005 + 1 = 57006.
You are a prisoner sentenced to death. The Emperor offers you a chance to live by playing a simple game. He gives you 50 black marbles, 50 white marbles and 2 empty bowls and instructs you to divide the 100 marbles into the two bowls. You can divide them however you want as long as all the marbles are in the bowls. You will be blindfolded and the bowls and marbles will be thoroughly mixed. You will then choose a single marble from one of the bowls. If the marble is white, you live. Black and you will be put to death.
How do you divide the marbles up so that you have the greatest probability of choosing a white marble?
Place one white marble in one bowl and place the rest of the marbles in the other bowl (49 whites, and 50 blacks).
This way you begin with a 50/50 chance of choosing the bowl with one white marble and living. Even if you choose the other bowl, you still have an almost 50% chance of picking one of the 49 white marbles. There are no guarantees in life, but this gives you the best change of surviving.