Question: A criminal is brought into a prison for major crimes. The warden informs him that he will be shot in the middle of the prison by 20 of his men. The prisoner is fine with that but he asks for some conditions "All of your men must stand 20 feet away from me and I must be able to select where each of them stands. If I survive, I get to leave."
The warden thinks about it and knows that all of his men will still have an open shot at the criminal, so he agrees.
The next day immediately after the firing squad is positioned the criminal walks out untouched. How did he do it?
Answer: He set up all of the warden's men so they are standing directly across from each other. None of them could fire at the criminal because they would risk hitting another man.
Question: There is a prison with 100 prisoners, each in separate cells with no form of contact. There is an area in the prison with a single light bulb in it. Each day, the warden picks one of the prisoners at random, even if they have been picked before, and takes them out to the lobby. The prisoner will have the choice to flip the switch if they want. The light bulb starts off.
When a prisoner is taken into the area with the light bulb, he can also say "Every prisoner has been brought to the light bulb." If this is true all prisoners will go free. However, if a prisoner chooses to say this and it's wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure.
Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves.
What strategy could they use to ensure they will go free?
Answer: Only allow one prisoner to turn the light bulb off and all of the others turn it on if they have never turned it on before. If they have turned it on before they do nothing. The prisoner that can turn it off then knows they have all been there and saves them all when he has turned it off 99 times.
By Albert Einstein
Question: There are 5 houses painted 5 different colors. In each house lives a person with a different nationality. These 5 people each drink a certain type of beverage, smoke a certain brand of cigar, and keep a certain pet. None of them have the same pet, smoke the same brand of cigar, or drink the same beverage.
The Brit lives in the red house.
The Swede keeps dogs as pets.
The Dane drinks tea.
The green house is on the left of the white house.
The green homeowner drinks coffee.
The person who smokes Pall Mall rears birds.
The owner of the yellow house smokes Dunhill.
The man living in the center house drinks milk.
The Norwegian lives in the first house.
The man who smokes Blend lives next to the one who keeps cats.
The man who keeps the horse lives next to the man who smokes Dunhill.
The owner who smokes Bluemaster drinks beer.
The German smokes prince.
The Norwegian lives next to the blue house.
The man who smokes Blend has a neighbor who drinks water.
Who owns the fish?
Answer: The German. It's easiest to solve this riddle by creating a grid organized by order of the houses, you can then fill in the house number of the Norwegian, the person who drinks milk, and the blue house:
These facts can all also be determined from the clues:
Brit - Red House
Swede - Dogs
Dane - Tea
Green House - Coffee
Pall Mall - Birds
Yellow House - Dunhill
Blue-masters - Beer
German - Prince
Green House is to left of the White House
Blends is next to Cats
Horse is next to Dunhill
Blends is next to Water
With this information these facts can be determined:
This info leads to a single color order:
The following information can now be determined:
With this version of the table we can now find the information pertaining to solving the riddle completely:
By Jane Austen
Question: When my first is a task to a young girl of spirit,
And my second confines her to finish the piece,
How hard is her fate! But how great is her merit
If by taking my whole she effects her release!
Question: Suppose you're on a game show, and you're given the choice of three doors: Behind one door is a sports car; behind all of the others is bicycles. You pick a door, say No. 1, and the host, who knows what's behind the doors, opens another door, say No. 2, revealing a bicycle. He then says to you, "Do you want to pick door No. 3?" Is it to your advantage to switch your choice?
Answer: Yes, by changing your answer your chances of winning actually goes up from 1/3 to 2/3.
This becomes obvious when expanding the example. Suppose there was 100 doors rather than 3. You pick one and the host shows you that the car is not behind 98 of the doors then asks you to switch to the remaining door or keep the door you picked. Of course you would switch your door because chances are you didn't pick the correct door initially.
For more explanation go to http://en.wikipedia.org/wiki/Monty_Hall_problem#Solutions