The Stanford Enigma
This problem was posed during a reflection test to students at the famous Stanford University.
Find out what the following sentences refer to:
- It's better than God.
- It's worse than the devil.
- The poor...
The challenge of the emir
A dying emir and feeling life leaving him brings his two sons to him.
He said to them, "You see on the horizon the minaret of the neighboring town?" Well, the...
Homeless man and cigarette butts
A homeless man is able to create a cigarette from 3 cigarette butts. Cunning as a fox, he manages to find 28 cigarette butts.
How many cigarettes will he get to...
A water lily doubles its surface
A water lily doubles its size everyday. Thirty days later, it covers up the whole pond it is on.
How many days did it take for it to cover the quarter...
The age of the two children
Emily and William are brothers and sisters. One day, the two children have a discussion in their rooms:
- You know Emily, if I took 2 years at my age and I...
The heaviest of the little bags of gold
We have 9 small bags of gold and a balance with 2 trays perfectly balanced. One of the small bags of gold is heavier than the others.
How can one identify...
The marriage of the cheating king and the princess
In an old Kingdom, there was a King known to be a great cheater. This King was in love with a young princess who refused each time her advances. One...
The bartender and the rifle
A man enters a bar and asks the bartender for a glass of water. The latter takes out his rifle and points it towards the newcomer, then tidies it up....
The dilemma of the farmer
A farmer has to cross a river with a wolf, a goat and a cabbage. For this, he has a boat but he can not leave together:
- The goat and...
The bulb and the 3 switches
You are in a room with 3 switches. Only one of these switches can light the bulb in the next room. A door gives access to the next room, but...
The 2 guards and the 2 doors
Two guards each watch a door. One of these doors leads to Paradise, and the other leads to Hell. We know that one of the guardians is always lying, while the other is only telling the truth. However, we do not know which guard is in front of which door. You want to go to heaven, and you have the right to only one question! Once the door is crossed, it is impossible to go back.
What question will you ask to be sure to find the right door?