Riddles
Optical Illusions
Math
Word Puzzles
Logic
100
A lift is on the ground floor. There are four people in the lift including me.
When the lift reaches first, floor, one person gets out and three people get in.
The lift goes up to the second floor, 2 people get out 6 people get in.
It then goes up to the next floor up, no-one gets out but 12 people get in. Halfway up to the next floor up the lift cable snaps, it crashes to the floor. Everyone else dies in the lift. How did I survive?
Answer: I got out on the second floor!
100
Which way is this spinning?
It is not.
100
How can I cut the board into only two pieces so that they will fill the hole exactly?
100
A man wanted to work, but he could not log in to his computer terminal successfully. He tried twice, but still his password did not work. He suddenly remembered that the passwords are reset every month for security purposes. So, he called his boss and said, “Hey boss, my password is out of date.”
His boss replied, “Yes, that’s right. The password is different. Listen carefully. I am sure, you can figure out the new one. The new one has the same amount of letters as your old password, but only four of the letters are the same.””Thanks boss.”With that, the man could correctly log into his station. What are both the new and old passwords?
Answer: The old one was “out of date.” The new one is “different.” Both passwords contain the letters d, f, e, and t
100
There is a bus. The bus is filled to the brim with kids. There is 10 on the right and 10 on the left. Which side of the bus is the door on?
What is the right side.
200
I have no voice, yet I speak to you.
I tell of all things in the world that people do.I have leaves, but I am not a tree.I have pages, but I am not a bride.I have a spine, but I am not a man.I have hinges, but I am not a door.I have told you all. I cannot tell you more.What am I?
Answer: A book
200
Are those Pacman?
no they are black circles with a white triangle over it.
200
The cold faucet in my bath lets the water in at the rate of 15 liters per minute.
The hot faucet fills the bath at the rate of 10 liters per minute.
The plug hole lets the water out of the bath at the rate of 12 liters per minute.
The bath holds a maximum of 520 liters.
I turn both faucets on, but forget to put the plug in. How many minutes does it take for the bath to overflow?
40 minutes.
Let's see how it's done:
Cold faucet fills at 15 liters / minute. Hot faucet fills at 10 liters / minute.
→ So water enters at 25 liters / minute. (15+10=25)
Plug hole empties at 12 liters / minute.
→ So bath fills up at 13 liters / minute. (25-12=13)
Bath hold 520 liters.
→ So bath overflows after 40 minutes. (520÷13=40)
(PS: don't try this at home, it just wastes fresh water!)
200
A man is headed to a mountain along with a lion, a goat, and a basket of vegetables. On the way, he needs to cross a river and the boat can only carry two things at a time. If he takes the vegetables, the lion will eat the goat. If he takes the lion, the goat will eat the vegetables. How does he cross the river?
Trip 1: He takes the goat with him, leaving the lion and the vegetables behind. On reaching the other riverbank, he drops off the goat.Trip 2: He then comes back for the lion, leaving the vegetables behind. On reaching the bank this time, he drops the lion, and again takes the goat along.Trip 3: He drops off the goat again and takes the vegetables with him to the other shore.Trip 4: Lastly, he comes back alone for the goat.
200
This week, we strike out for yet another island in the archipelago of knights and knaves. On this island, there are no spies, only knights who always tell the truth, and knaves who always lie. But these knights and knaves are of an older clan, and they do not speak English. They understand English perfectly well, but will only respond with "da" and "ja."
The words mean "yes" and "no," but which is which, you do not know.
On the island of knights and knaves, you are approached by a man. He will only respond to you with "da" or "ja."
How do you figure out if he is a knight or knave with just one question?
Down the road, you meet another man. Let's say you don't care if he is a knight or knave, you just want to know the meanings of "ja" and "da." How do you figure this out with just one question?
To figure out if the fellow is a knight or knave, simply ask him, "does ja mean yes?" If he says "ja," he is a knight. If he says "da," he is a knave.
Let's say, for this example, that "ja" means "yes." To answer your question, the knight would say "ja," or yes, it means yes. If "ja" means no, then the knight would still say "ja," meaning no, it does not mean yes. The knave, alternatively, would lie to you about these things, and so give you the opposite word, "da."
To figure out what the words mean, without knowing if the fellow is a knight or a knave, you ask, "are you a knight?" Either way, they will say "yes," so whichever word they use is the affirmative one.
Interestingly enough, to figure out if the person is a knight or a knave, you ask what the words mean, and to figure out what the words mean, you ask if the person is a knight. The person's response, though it does not answer your question, gives you information.
Make sure to keep this in mind when wandering in foreign lands, and make sure to come back next week for another riddle!
300
You are in a room that has three switches and a closed door. The switches control three light bulbs on the other side of the door. Once you open the door, you may never touch the switches again. How can you definitively tell which switch is connected to each of the light bulbs?
Turn on the first two switches. Leave them on for 5 minutes. Once 5 minutes has passed, turn off the second switch, leaving one switch on. Now go through the door. The light that is still on is connected to the first switch. Whichever of the other two is warm to the touch is connected to the second switch. The bulb that is cold is connected to the switch that was never turned on!
300
Are these people?
Yes
300
The circumference of the Earth is approximately 40,000 kilometers, and someone has just made a metal band that circles the Earth, touching the ground at all locations.
You come along at night, as a practical joke, and add just 10 meters to its length (one hundredth of one kilometer !)
It is now one four-millionth longer, and sits magically just above the ground at all locations
How far has it risen ... could a flea, a rabbit or even a man squeeze underneath it?
Use the formula:
Circumference = 2 × π × Radius
Where π is the famous number "pi" equal to 3.14159....
Before: Original Circumference = 2 × π × R
After: Original Circumference + 10m = 2 × π × (R + Gap)
Subtracting the two:
10m = 2 × π × Gap
So, the Gap = 10m / (2 × π) = 1.6m approximately
So a man could fit under it easily (though he might bump his head)
Note: Adding 10m to the circumference of ANY circle increases the radius by 10m / (2 × π), no matter what the original circumference was.
300
There is a fishing trawler, with a ladder in it, leaning against a wall at the harbor. There are five oars and two fishing nets in the trawler. The distance between two consecutive steps on the ladder is 1 meter. If waves lashing against the wall rise half meter in every half hour, in how much time will six steps of the ladder get under the waves?
The trawler rises with the waves, so no steps will go under water.
300
In which direction is the bus pictured below traveling?
Do you know the answer?
The only possible answers are “left” or “right.”
When pre-school children are shown this brain teaser, they often answer “left.” Why? “Because you can’t see the door.”
400
I left my campsite and hiked south for 3 miles. Then I turned east and hiked for 3 miles. I then turned north and hiked for 3 miles, at which time I came upon a bear inside my tent eating my food! What color was the bear?
White. The only place you can hike 3 miles south, then east for 3 miles, then north for 3 miles and end up back at your starting point is the North Pole. There are only polar bears in the North Pole, and they are white!
400
Optical Illusion
400
A magic rectangular belt always shrinks its length to 1/2 and width to 1/3 whenever its owner wishes something.
After three such wishes, its surface is now 4 cm2.
What was the original length, if the original width was 9 cm?
The original length of the belt was 96 cm.
96×9 became 48×3, then 24×1, then 12×(1/3)
400
A man is on a game show. He is presented with two doors, one on the left, and one on the right. Behind one is 2 million dollars, and behind the other is a donkey. Choose the correct door to win the prize. There are also two men in front of the doors, and they know which door leads to the millions. One wears a black hat, and the other wears a white hat.The host explains that one of the men is a liar, and will always lie, and the other man will always tell the truth – but you do not know which is which.You can ask only one of the men only one question. What is the question, and which man do you ask to ensure you win the money?
Answer: You ask either man the following question: “If I asked the other guy which door has the money, what would he say?” and then choose the opposite door. Work it out: If you ask the question to the liar, he will lie about the ‘correct’ answer, so you must choose the opposite door. If you ask the truth teller, he will tell the truth about the lie, so you can choose the opposite door as well.
400
Where do words go?
Words are stored in the temporal lobe of your brain
500
Crime Scene: A large wooden box was built with one door. The door was locked from the inside, and then nailed shut from the inside. The police break into the room. In the middle of the room there is a dead man hanging from the ceiling, with his shoes 3 feet off the ground. The only other thing in the room is a hammer lying in a puddle of water. Can you explain what happened?
He committed suicide by hanging himself when the ice melted.
500
Are these animals?
Yes
500
A car has to carry an important person across the desert.
There is no petrol station in the desert and the car has space only for enough petrol to get it half way across the desert.
There are also other identical cars that can transfer their petrol into one another.
How can we get this important person across the desert?
We need 4 cars (including the car with the important person).
All 4 cars start full.
At 1/6th of the way, all cars are 2/3rds full. One car sacrifices itself and fills up two of the other cars. Two cars are now full, one is 2/3rds full. (An empty car is left behind.)
At 2/6th of the way, two cars are 2/3rds full. One car is one third full, and sacrifices itself to fill up one of the other cars. One car is now full, one is 2/3rds full. (An empty car is left behind.)
At half way, one car is 2/3rds full. One car is one third full, and sacrifices itself to fill the other car, which is now full and can make the other half of the journey.
500
An Arab sheik is old and must will his fortune to one of his two sons. He makes a proposition. His two sons will ride their camels in a race, and whichever camel crosses the finish line LAST will win the fortune for its owner. During the race, the two brothers wander aimlessly for days, neither willing to cross the finish line. In desperation, they ask a wise man for advice. He tells them something; then the brothers leap onto the camels and charge toward the finish line. What did the wise man say?
The rules of the race were that the owner of the camel that crosses the finish line last wins the fortune. The wise man simply told them to switch camels.
500
Is the inner shape a real circle?
Believe it or not, both shapes are perfect circles