The Prime Number Riddle
Two hundred people in an auditorium are asked to think of a single digit number from 1 to 9 inclusive and write it down. All those who wrote down a prime number are now asked to leave. Ninety people remain behind in the hall. How many of these are expected to have written down an odd number?
Hint: Remember that 1 is not a prime number.
Those that remain behind must have written {1,4,6,8,9} and from this only {1,9} are odd. The probability of an odd number is thus 2/5.
Expected number of odds is 2/5 * 90 = 36 Did you answer this riddle correctly?
YES NO
Expected number of odds is 2/5 * 90 = 36 Did you answer this riddle correctly?
YES NO
The 3 Inch Cube Riddle
A 3 inch cube is painted on all sides with RED. The cube is then cut into small cubes of dimension 1 inch. All the so cut cubes are collected and thrown on a flat surface. What is the probability that all the top facing surfaces have RED paint on them?
Hint: Visualize the core of the cube.
ZERO.
The core of the 3 inch cube when cut, has all faces that are not painted. Hence at least one cube with no painted face always occurs. Did you answer this riddle correctly?
YES NO
The core of the 3 inch cube when cut, has all faces that are not painted. Hence at least one cube with no painted face always occurs. Did you answer this riddle correctly?
YES NO
Fighting In A Truel
Mr. Black, Mr. Gray, and Mr. White are fighting in a truel. They each get a gun and take turns shooting at each other until only one person is left. Mr. Black, who hits his shot 1/3 of the time, gets to shoot first. Mr. Gray, who hits his shot 2/3 of the time, gets to shoot next, assuming he is still alive. Mr. White, who hits his shot all the time, shoots next, assuming he is also alive. The cycle repeats. All three competitors know one another's shooting odds. If you are Mr. Black, where should you shoot first for the highest chance of survival?
Hint: Think from the points of view of Mr. Gray and Mr. White, not just Mr. Black.
He should shoot at the ground.
If Mr. Black shoots the ground, it is Mr. Gray's turn. Mr. Gray would rather shoot at Mr. White than Mr. Black, because he is better. If Mr. Gray kills Mr. White, it is just Mr. Black and Mr. Gray left, giving Mr. Black a fair chance of winning. If Mr. Gray does not kill Mr. White, it is Mr. White's turn. He would rather shoot at Mr. Gray and will definitely kill him. Even though it is now Mr. Black against Mr. White, Mr. Black has a better chance of winning than before. Did you answer this riddle correctly?
YES NO
If Mr. Black shoots the ground, it is Mr. Gray's turn. Mr. Gray would rather shoot at Mr. White than Mr. Black, because he is better. If Mr. Gray kills Mr. White, it is just Mr. Black and Mr. Gray left, giving Mr. Black a fair chance of winning. If Mr. Gray does not kill Mr. White, it is Mr. White's turn. He would rather shoot at Mr. Gray and will definitely kill him. Even though it is now Mr. Black against Mr. White, Mr. Black has a better chance of winning than before. Did you answer this riddle correctly?
YES NO
The Emperor's Proposition Riddle
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?
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 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 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. Did you answer this riddle correctly?
YES NO
This way you begin with 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. Did you answer this riddle correctly?
YES NO
Hundreds Of These In A Graveyard
There are hundreds of these in a graveyard
But dead bodies it is not
Its what contains all the info as to
Whos in each burial plot
What is it?
But dead bodies it is not
Its what contains all the info as to
Whos in each burial plot
What is it?
Hint:
An Area With Little Rain
This is an area with little rain
So youre unlikely to see many trees
Kalahari, Negev, Atacama
Gobi and Sahara what are all these?
So youre unlikely to see many trees
Kalahari, Negev, Atacama
Gobi and Sahara what are all these?
Hint:
Sherlock Holmes And The Case Of Ganpat
Ganpat is found dead in his office at his desk.
Sherlock Holmes was working on this case and have narrowed the suspects down to three people:
1. His Friend Mr Rakesh Gupta
2. Ganpat's wife "Bhawna"
3. His Secretary "Jason Kumar"
All three suspects visited ganpat on the day of his murder for various reason as they told to sherlock.
As we know where police failed , sherlock comes.
He was able to find a note at the corner of the wall. "7B91011" was written on it.
Sherlock waste no time in announcing the killer. Who was the killer ?
Sherlock Holmes was working on this case and have narrowed the suspects down to three people:
1. His Friend Mr Rakesh Gupta
2. Ganpat's wife "Bhawna"
3. His Secretary "Jason Kumar"
All three suspects visited ganpat on the day of his murder for various reason as they told to sherlock.
As we know where police failed , sherlock comes.
He was able to find a note at the corner of the wall. "7B91011" was written on it.
Sherlock waste no time in announcing the killer. Who was the killer ?
Hint:
Jason Kumar
The number on the calendar was written in a hurry.Sherlock matched the written number with the months of the year.
So the B was an 8, thereby giving us 7-8-9-10-11: July, August, September, October, November.
Use the first letter of each month and it spells J-A-S-O-N. Did you answer this riddle correctly?
YES NO
The number on the calendar was written in a hurry.Sherlock matched the written number with the months of the year.
So the B was an 8, thereby giving us 7-8-9-10-11: July, August, September, October, November.
Use the first letter of each month and it spells J-A-S-O-N. Did you answer this riddle correctly?
YES NO
The Murder Of Ray Whitcombe
Ray Whitcombe is found dead in his office at his desk. The police have narrowed the suspects down to three people: Mrs. Barbara Whitcombe, Ray's wife; Mr. Jason McCubbins, Ray's business partner; and Mr. Harold Nichols, Ray's best friend. All three visited Mr. Whitcombe the day of his murder, but all three provide the police with stories of explanation as to the reason for their visit. Police found Mr. Whitcombe with his wrist watch still on his right arm, a torn up picture of his wife laying on the floor beside the trash can, and an ink pen in his right hand. On the desk, the police found a name plate, a telephone that was off the hook, and a personal calendar turned to the July 5th page with 7B91011 written on it. After examining this evidence, the police knew their suspect. Who was it?
Hint:
Jason McCubbins, Ray's business partner. The calendar is the clue to solving this murder. The police realized that since Mr. Whitcombe was wearing his watch on his right arm, he must be left handed. But the pen was found in his right hand. Realizing that the number on the calendar was written in a hurry and with his opposite hand, police matched the written number with the months of the year. So the B was an 8, thereby giving us 7-8-9-10-11: July, August, September, October, November. Use the first letter of each month and it spells J-A-S-O-N. Did you answer this riddle correctly?
YES NO
YES NO
Youre Fired Riddle
A man is leaving on a business trip and stops by his office on the way to the airport. The night watchman stops him and says, Sir, dont take that flight. I had a dream last night that your plane would crash and everyone would die! The business man cancels his trip and sure enough, the plane crashes, killing all the passengers. The man gives his watchman a $10,000 reward for saving his life, then fires him. Why?
Hint:
Getting Rid Of Dirt
But it doesn't clean your shirt
You push it all over the floor
And it sucks up all the dirt
Hint:
In The Bathroom
If you go to the UK
British people call them loos
You find them in the bathroom
They're for number ones and twos
British people call them loos
You find them in the bathroom
They're for number ones and twos
Hint:
A Single Item
Your boss gives you $10 and tells you to buy; Something for him to eat. Something for him to drink. Something to feed his cows and something to plant in his garden. And most importantly you can buy only a single item that meets all these criteria. What do you buy?
Hint:
Puddle On The Ground
If a the police were investigating a suicide and all there was was a man hanging from the roof a collapsed wood box and a puddle on the ground and a match found inside the box how did this man die.
Hint:
He was standing on a box with ice in it he threw a match in the hole in the box it eventually melted the ice and made the wooden box collapse Did you answer this riddle correctly?
YES NO
YES NO
Gay Detectives Riddle
Hint:
Am Room With Windows Riddle
In a room with four walls no windows. On the south wall there is a door and on the north too. There is a table in the middle with four chairs. On the table there are 52 bicycles and three empty boxes in one of the chairs there is a dead man. How did he die?
Hint:
How he died was he was in a submarine and they were at war with another country and their ship was hit there were four people in there. The bicycles are actually playing card brands and there were three oxygen tanks. the four men bet with cards to see who would get to take one oxygen tank. obviously the man who was dead lost and he was the one who died from lack of oxygen in the sub. Did you answer this riddle correctly?
YES NO
YES NO
Add Your Riddle Here
Have some tricky riddles of your own? Leave them below for our users to try and solve.