Riddle #967

logic

Prisoner sentenced to death

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. He then says, "Divide these 100 marbles into these 2 bowls. You can divide them any way you like as long as you use all the marbles. Then I will blindfold you and mix the bowls around. You then can choose one bowl and remove ONE marble. If the marble is WHITE you will live, but if the marble is BLACK... you will die." How do you divide the marbles up so that you have the greatest probability of choosing a WHITE marble? HINT: The answer does not guarantee 100% you will chose a white marble, but you have a much better chance.
Place 1 white marble in the bowl, and place the rest of the marbles in the other bowl (49 whites, and 50 blacks). This way you begin a 50/50 chance of choosing the bowl with just one white marble, therefore life! BUT even if you choose the other bowl, you still have almost a 50/50 chance at picking one of the 49 white marbles.
90.47 %
44 votes

Similar riddles

See also best riddles or new riddles.

logic

Round Manhole Covers

Why are manhole covers round? Do manhole covers really need to be circular?
Manhole covers are round so that they won't fall through the hole into the sewer below them. No matter how you turn the cover, you won't be able to push the cover through the hole. However, if you were to have square manhole covers, you would be able to rotate the cover such that one of the edges of the square cover is lined up with the diagonal line of the square hole, which would allow the cover to fall through, causing countless problems that the general public would rather avoid.
92.86 %
35 votes

cleanfunnylogic

A woman with no driver license

A woman with no driver license goes the wrong way on a one-way street and turns left at a corner with a no left turn sign. A policeman sees her but does nothing... Why?
She is walking.
93.70 %
40 votes

cleanlogic

Smartest kid in the world

Jake and his friend Paco had very famous challenge sessions at their school. One would suggest something they could do, and the other would prove it wrong somehow. One day, Jake surprised Paco by stating: "I can answer any question in the world." Sure that he would win the challenge, Paco accepted the task of proving it wrong. He wrote up a test full of impossible questions. After a while, Jake returned the test. Paco unbelievably lost the challenge and told Jake he could indeed answer any question. How did Jake win?
For all the impossible questions, Jake simply wrote "I don't know".
93.84 %
41 votes

logicmystery

The greatest mystery ever

Paul is 20 years old in 1980, but only 15 years old in 1985. How is this possible?
The years are in B.C., not A.D. as you probably assumed. Based on the system we use to number the years, the years counted down in B.C. (but they weren't counting backwards back then).
90.04 %
42 votes

logic

Just one match

If you had one match and entered a room in which there were a kerosene lamp, an oil burner, and a wood burning stove, which would you light first?
The match.
92.67 %
34 votes

logic

3 parachutes

The Pope, Beyonce, Barack Obama, and Bill Gates are on the same plane. There are only 3 parachutes left for the 4 of them. Obama says: "As the President, I think I should have the right to have a parachute, because I rule millions of people in the greatest nation of all." Beyonce says: "As one of the greatest singers of all-time, I think I should deserve to be safe. I bring tears and laughter to millions of people, and I'm an important contributor to pop music." Bill Gates says: "As one of the richest successful company owners, I think I should live because I'm on top of the economics cycle, creating jobs and incomes for millions of people. I am a wealthy and intelligent man." Finally, the Pope says: "I'm an old, religious man. I lived a life that's full, I helped millions of people find their way through God, I'm ready to let go of a parachute and to face my fate." Which one of them will abandon the parachute and die?
Did I ever mention that the plane was crashing? No one's gonna die.
94.59 %
47 votes

funnylogic

Men at work

Two men working at a construction site were up for a challenge, and they were pretty mad at each other. Finally, at lunch break, they confronted one another. One man, obviously stronger, said "See that wheelbarrow? I'm willin' to bet $100 (that's all I have in my wallet here) that you can't wheel something to that cone and back that I can't do twice as far. Do you have a bet?" The other man, too dignified to decline, shook his hand, but he had a plan formulating. He looked at the objects lying around: a pile of 400 bricks, a steel beam, the 10 men that had gathered around to watch, his pickup truck, a stack of ten bags of concrete mix, and then he finalized his plan. "All right," he said, and revealed his object. That night, the strong man went home thoroughly teased and $100 poorer. What did the other man choose?
He looked the man right in the eye and said "get in."
93.98 %
42 votes

cleanlogic

Two ropes burning

You have two lengths of rope. Each rope has the property that if you light it on fire at one end, it will take exactly 60 minutes to burn to the other end. Note that the ropes will not burn at a consistent speed the entire time (for example, it's possible that the first 90% of a rope will burn in 1 minute, and the last 10% will take the additional 59 minutes to burn). Given these two ropes and a matchbook, can you find a way to measure out exactly 45 minutes?
The key observation here is that if you light a rope from both ends at the same time, it will burn in 1/2 the time it would have burned in if you had lit it on just one end. Using this insight, you would light both ends of one rope, and one end of the other rope, all at the same time. The rope you lit at both ends will finish burning in 30 minutes. Once this happens, light the second end of the second rope. It will burn for another 15 minutes (since it would have burned for 30 more minutes without lighting the second end), completing the 45 minutes.
94.59 %
47 votes

cleanlogicshort

Next letter

What letter is next in this sequence? M, A, M, J, J, A, S, O,__
N for November.
93.55 %
39 votes