Brain Teasers & Puzzles

100 prisoners are stuck in the prison in solitary cells. The warden of the prison got bored one day and offered them a challenge. He will put one prisoner per day, selected at random (a prisoner can be selected more than once), into a special room with a light bulb and a switch which controls the bulb. No other prisoners can see or control the light bulb. The prisoner in the special room can either turn on the bulb, turn off the bulb or do nothing. On any day, the prisoners can stop this process and say “Every prisoner has been in the special room at least once”. If that happens to be true, all the prisoners will be set free. If it is false, then all the prisoners will be executed. The prisoners are given some time to discuss and figure out a solution. How do they ensure they all go free?
View SolutionSubmit Solution 968.9K views
 1 answers
 0 votes

A certain town comprises of 100 married couples. Everyone in the town lives by the following rule: If a husband cheats on his wife, the husband is executed as soon as his wife finds out about him. All the women in the town only gossip about the husbands of other women. No woman ever tells another woman if her husband is cheating on her. So every woman in the town knows about all the cheating husbands in the town except her own. It can also be assumed that a husband remains silent about his infidelity. One day, the mayor of the town announces to the whole town that there is at least 1 cheating husband in the town. What do you think happens?
View SolutionSubmit Solution 975.1K views
 1 answers
 2 votes

When can you add 2 to 11 to get 1 as the correct answer?
Hint: many possible
View SolutionSubmit Solution 969.9K views
 3 answers
 1 votes

A bridge will collapse in 17 minutes.
4 people want to cross it before it will collapse. It is a dark night and there is only one torch between them.
Only two people can cross at a time.
“A” takes a minute to cross.
“B” takes 2 minutes.
“C” takes 5
and “D” takes 10 minutesHow do they all cross before the bridge collapses?
View SolutionSubmit Solution 988.1K views
 2 answers
 2 votes

Albert and Bernard just became friends with Cheryl, and they want to know when her birthday is. Cheryl gives them a list of 10 possible dates.
May 15 16 19
June 17 18
July 14 16
August 14 15 17
Cheryl then tells Albert and Bernard separately the month and the day of her birthday, respectively.
Albert: I don’t know when Cheryl’s birthday is, but I know that Bernard does not know, too.
Bernard: At first, I didn’t know when Cheryl’s birthday is, but I know now.
Albert: Then I also know when Cheryl’s birthday is.
When is Cheryl’s birthday?
View SolutionSubmit Solution 968.5K views
 1 answers
 0 votes

The owner of a banana plantation has a camel. He wants to transport his 3000 bananas to the market, which is located after the desert. The distance between his banana plantation and the market is about 1000 kilometer. So he decided to take his camel to carry the bananas. The camel can carry at the maximum of 1000 bananas at a time, and it eats one banana for every kilometer it travels.
What is the most bananas you can bring over to your destination?
View SolutionSubmit Solution 976.1K views
 1 answers
 0 votes

You have 100 doors in a row that are all initially closed. you make 100 passes by the doors starting with the first door every time. the first time through you visit every door and toggle the door (if the door is closed, you open it, if its open, you close it). the second time you only visit every 2nd door (door #2, #4, #6). the third time, every 3rd door (door #3, #6, #9), ec, until you only visit the 100th door.
What state are the doors in after the last pass? Which are open which are closed?
Puzzle asked in: Google,Adobe,Amazon,OracleView SolutionSubmit Solution 976.5K views
 2 answers
 0 votes

There is a building of 100 floors
If an egg drops from the Nth floor or above it will break.
If it’s dropped from any floor below, it will not break.
You’re given 2 eggs.
Find NHow many drops you need to make?
What strategy should you adopt to minimize the number egg drops it takes to find the solution?View SolutionSubmit Solution 1,132.7K views
 15 answers
 2 votes

You are blindfolded and 10 coins are place in front of you on table.
You are allowed to touch the coins, but can’t tell which way up they are by feel. You are told that there are 5 coins head up, and 5 coins tails up but not which ones are which.
How do you make two piles of coins each with the same number of heads up?
View SolutionSubmit Solution 979.5K views
 1 answers
 1 votes

Prove that p^2 – 1 is divisible by 24 if p is a prime number greater than 3?
View SolutionSubmit Solution 970.5K views
 1 answers
 1 votes
More puzzles to try
Is the square in the middle a perfect square?
Is the square in the middle a perfect square? Although it is a perfect square, the sides may appear to ...Read More »How cannot even a single one died by explosion
A bomb exploded in a room full of married couples and not even a single one died. How ?Read More »Always smile back
If you drop me, I am sure to crack. Give me a smile, and I will always smile back. What ...Read More »Five greedy pirates and gold coin distribution Puzzle
Five puzzleFry ship’s pirates have obtained 100 gold coins and have to divide up the loot. The pirates are all ...Read More »Spine but no bones
What has a spine, but no bones?Read More »Solve the murder mystery
A couple went to river rafting on a hill station. Two days after their departure, the husband returned alone. He ...Read More »Shepherd & Sheep riddle
4 shepherds were watching over their flocks and they were commenting on how many sheep they each had. If Alan ...Read More »During what month do people sleep the least?
During what month do people sleep the least?Read More »Why did the man thank the bartender?
A man runs into a bar and asks for a glass of water. The bartender pulls out a shotgun and ...Read More »Black and admired
Black he is and much admired, men seek him until they’re tired. When they find him, they break his head, ...Read More »Question in probability exam What is risk puzzle
There was once a college that offered a class on probability applied to the real world.The class was relatively easy, ...Read More »Making Traingles
Make 4 triangles by moving the position of only one pencil.Read More »Who visited Which place puzzle
In Mulund, the shoe store is closed every Monday, the boutique is closed every Tuesday, the grocery store is closed ...Read More »Adding letter riddle
What word starting with BR, that with the addition of the letter E, becomes another word that sounds the same ...Read More »Odd in Group
Below are set of four words, one of which does not belong with the other three. Which word does not ...Read More »The ProgressionMathematics Problem
Suppose that there is a rubber ball which has a property of bouncing back to the original height from which ...Read More »Find the time man walked
A man I know, who lives in my neighborhood, travels to Chinsura every day for his work. His wife drives ...Read More »What does it means riddle
What does this mean? Pot ooooooooRead More »The Botanist
At a farm, you are asked to identify these common plants from their blooms:Read More »Group of three riddle
There is a group of three. One is sitting down, and will never get up. The second eats as much ...Read More »