Philosopher's clock

One absentminded ancient philosopher forgot to wind up his only clock in the house. He had no radio, TV, telephone, internet, or any other means for telling time. So he traveled on foot to his friend's place few miles down the straight desert road. He stayed at his friend's house for the night and when he came back home, he knew how to set his clock.
How did he know?

Ans:
Clocks can measure time even when they do not show the right time. You just have to wind the clock up and... 
We have to suppose that the journey to the friend and back lasts exactly the same time and the friend has a clock (showing the correct time) - it would be too easy if mentioned in the riddle.
Now there is no problem to figure out the solution, is there?

Camel Race

An Arab sheikh tells his two sons to race their camels to a distant city to see who will inherit his fortune. The one whose camel is slower wins. After wandering aimlessly for days, the brothers ask a wise man for guidance. Upon receiving the advice, they jump on the camels and race to the city as fast as they can.
What did the wise man say to them?

Ans:
The wise man told them to switch camels.

Magnet

This logic puzzle was published in Martin Gardner's column in the Scientific American. You are in a room with no metal objects except for two iron rods. Only one of them is a magnet.
How can you identify which one is a magnet?

Ans:
You can hang the iron rods on a string and watch which one turns to the north (or hang just one rod).
Gardner gives one more solution: take one rod and touch with its end the middle of the second rod. If they get closer, then you have a magnet in your hand.
The real magnet will have a magnetic field at its poles, but not at its center. So as previously mentioned, if you take the iron bar and touch its tip to the magnet's center, the iron bar will not be attracted. This is assuming that the magnet's poles are at its ends. If the poles run through the length of the magnet, then it would be much harder to use this method. 
In that case, rotate one rod around its axis while holding an end of the other to its middle. If the rotating rod is the magnet, the force will fluctuate as the rod rotates. If the rotating rod is not magnetic, the force is constant (provided you can keep their positions steady).

The Elevator Trouble

A man who lives on the tenth floor takes the elevator down to the first floor every morning and goes to work. In the evening, when he comes back; on a rainy day, or if there are other people in the elevator, he goes to his floor directly. Otherwise, he goes to the seventh floor and walks up three flights of stairs to his apartment. 
Can you explain why?
(This is one of the more popular and most celebrated of all lateral thinking logic puzzles. It is a true classic. Although there are many possible solutions that fit the conditions, only the canonical answer is truly satisfying.)

Ans:
The man is of short stature. He can't reach the upper elevator buttons, but he can ask people to push them for him. He can also push them with his umbrella.

Trapped Ping Pong Ball

Your last good ping-pong ball fell down into a narrow metal pipe imbedded in concrete one foot deep. 
How can you get it out undamaged, if all the tools you have are your tennis paddle, your shoe-laces, and your plastic water bottle, which does not fit into the pipe?

Ans:
All the tools are random things that are not going to help you. All you have to do is pour some water into the pipe so that the ball swims up on the surface. And if you say that you don't have any water, then think about what you drank today and if you can use that somehow :-)

Sequences

There are infinite formulas that will fit any finite series. Try to guess the following number in each sequence (using the most simple mathematical operations, because as I mentioned, there is more than one solution for each number sequence.

1. 8723, 3872, 2387, ?
2. 1, 4, 9, 18, 35, ?
3. 23, 45, 89, 177, ?
4. 7, 5, 8, 4, 9, 3, ?
5. 11, 19, 14, 22, 17, 25, ?
6. 3, 8, 15, 24, 35, ?
7. 2, 4, 5, 10, 12, 24, 27, ?
8. 1, 3, 4, 7, 11, 18, ?
9. 99, 92, 86, 81, 77, ?
10. 0, 4, 2, 6, 4, 8, ?
11. 1, 2, 2, 4, 8, 11, 33, ?
12. 1, 2, 6, 24, 120, ?
13. 1, 2, 3, 6, 11, 20, 37, ?
14. 5, 7, 12, 19, 31, 50, ?
15. 27, 82, 41, 124, 62, 31, 94, 47, 142, 71, 214, 107, ?
16. 126, 63, 190, 95, 286, 143, 430, 215, 646, 323, 970, ?
17. 4, 7, 15, 29, 59, 117, ?
18. 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, ?
19. 4, 4, 341, 6, 4, 4, 6, 6, 4, 4, 6, 10, 4, 4, 14, 6, 4, 4, 6, 6, 4, 4, 6, 22, 4, 4, 9, 6, ?

Ans:

1. 8723, 3872, 2387, ? 7238 (moving of numerals)
2. 1, 4, 9, 18, 35, ? 68 (x*2+2, +1, +0, -1, -2)
3. 23, 45, 89, 177, ? 353 (x*2-1)
4. 7, 5, 8, 4, 9, 3, ? 10, 2 (two series - every second number: 7, 8, 9, 10 and 5, 4, 3, 2)
5. 11, 19, 14, 22, 17, 25, ? 20, 28 (two series - every second number: 11, 14, 17, 20 and 19, 22, 25, 28)
6. 3, 8, 15, 24, 35, ? 48 (x+5, +7, +9, +11, +13)
7. 2, 4, 5, 10, 12, 24, 27, ? 54, 58 (x*2, +1, *2, +2, *2, +3, *2, +4)
8. 1, 3, 4, 7, 11, 18, ? 29 (a+b=c, b+c=d, c+d=e)
9. 99, 92, 86, 81, 77, ? 74 (x-7, -6, -5, -4, -3)
10. 0, 4, 2, 6, 4, 8, ? 6 (x+4, -2, +4, -2, +4, -2)
11. 1, 2, 2, 4, 8, 11, 33, ?
12. 1, 2, 6, 24, 120, ? 720 (x*2, *3, *4, *5, *6)
13. 1, 2, 3, 6, 11, 20, 37, ?
14. 5, 7, 12, 19, 31, 50, ? 81 (a+b=c, b+c=d, c+d=e)
15. 27, 82, 41, 124, 62, 31, 94, 47, 142, 71, 214, 107, ? 322, 161 (x*3+1, /2, *3+1, /2)
16. 126, 63, 190, 95, 286, 143, 430, 215, 646, 323, 970, ? 485, 1456 (x/2, *3+1, /2, *3+1)
17. 4, 7, 15, 29, 59, 117, ? 235 (x*2-1, *2+1, *2-1)
18. 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5, ? 2, 3, 2, 3, 2, 4, 2, 3, 2, 3, 2, 5
19. 4, 4, 341, 6, 4, 4, 6, 6, 4, 4, 6, 10, 4, 4, 14, 6, 4, 4, 6, 6, 4, 4, 6, 22, 4, 4, 9, 6, ? 4, 4

Mathematical Symbol

What mathematical symbol can be placed between 5 and 9, to get a number greater than 5 and smaller than 9?

Ans:

decimal point (5.9)

Birthday!

The day before yesterday I was 25 and the next year I will be 28. This is true only one day in a year.
What day is my birthday?

Ans:
He was born on December 31st and spoke about it on January 1st.
The day before yesterday(December 30), he was 25 yrs old.
On the 31st, he turned 26.
On the 31st of December of current year, he will turn 27
And finally on the 31st December of next year, he will turn 28.

The Casanova

Something to relax. A slim young man asked a girl on a date:
"I say something. If it is truthful, will you give me your photo?"
"Yes," replied miss.
"And if it is a lie, do not give me your photograph. Would you promise that?"
The girl agreed. Then the chap said such a sentence, that after a little while of thinking she realized, that if she wanted to honor her promise, she wouldn't have to give him a photo but a kiss.
What would you say (if you were him) to be kissed and so on?

Ans:

You could say for instance this sentence: "You will give me neither your photo nor a kiss."

Coins

Imagine there are 3 coins on the table: gold, silver, and copper. If you make a truthful statement, you will get one coin. If you make a false statement, you will get nothing.
What sentence can guarantee you getting the gold coin?

Ans:
"You will give me neither copper nor silver coin." If it is true, then I have to get the gold coin. If it is a lie, then the negation must be true, so "you give me either copper or silver coin", which would break the given conditions that you get no coin when lying. So the first sentence must be true.

5 questions!

#1.Brothers and sisters I have none but this man's father is my father's son.Who is the man?


 #2.Feed me and I live, yet give me a drink and I die.


#3.What is at the end of a rainbow?


#4.What has one eye but cannot see?


#5.What is always coming but never arrives?

So have you guessed your answers?


Ans:
#1.The man is my son
#2.Fire
#3. The word 'W'
#4. A needle
#5. Tommorow

The Riddle Of The Sphinx.

Which creature walks on four legs in the morning, two legs in the afternoon, and three legs in the evening?

Ans:
Man. 
He crawls on all fours as a baby, then walks on two feet as an adult, and then walks with a cane as an old man.

Brothers and sisters I have none...

Brothers and sisters I have none but this man's father is my father's son.
Who is the man?

Ans:

Answer to this riddle is simple - the man is my son.

Put The Numbers!

Place the numbers 1 to 6 in the circles so that each number is the difference between the two numbers just below it.

Ans:

      2
   3       5
4     1     6

Brain Exercise

Do you feel like your brain is free at this time! Want to do some brain exercise? Well if your answer is yes, try these brain exercise.

1. Say the days of the week back­wards, then in alpha­bet­i­cal order.
2. Say the months of the year in alpha­bet­i­cal order. Easy? well, why don’t you try doing so back­wards, in reverse alpha­bet­i­cal order.
3. Find the sum of your date of birth, mm/dd/yyyy. Want more exer­cise? Do the same with friends’ and rel­a­tives’ date of birth.
4. Name two objects for every let­ter in your com­plete name. Work up to five objects, try­ing to use dif­fer­ent items each time.
5. Wher­ever you are, look around and within two min­utes, try to find 5 red things that will fit in your pocket, and 5 blue objects that are too big to fit.

Brain Teaser To Test Your Attentional Focus

Try this exercise to test your atten­tional focus and multi-tasking abil­i­ties. Three words have been com­bined to make the grid of let­ters above. How many times does each of these words appear…? Can you com­pare your per­for­mance while search­ing for just one word vs. two of them at the same time? (or even the three of them, if you feel ambitious?)

How many times is the word SUN shown?
How many times is the word BUS shown?
How many times is the word NONE shown?

Count The F's

FINISHED FILES ARE THE RESULT OF YEARS OF SCIENTIFIC STUDY COMBINED 

WITH THE EXPERIENCE OF YEARS.

Count correctly how many 'F' are there in the sentence above. I challenge you! 

Ans:

FINISHED FILES ARE THE
RESULT OF YEARS OF SCIENTIFIC
STUDY COMBINED WITH THE
EXPERIENCE OF YEARS

So the correct answer is 6

Almost everyone guesses three. Why? It seems that the brain cannot correctly process the word "OF". The letter F usually makes the "f" sound, like in "fox". However, in the word "of", it makes a "v" sound. Somehow, your brain overlooks the word "of" as it scans for the sound of "f".

Count the men!

Look at the image and count how many people are in the picture. After the image shifts count again how many individuals are there. Where did the extra person come from?

Even though there is nothing added to the image or taken from it, there seem to be an extra additional person. Try to find some clues.

This mysterious illusion is just one of the many resources of the optical illusions showing how the brain can be fooled. Don't you wonder what other aspects in life we take for granted could be very different from how we perceive them?

Hallucination.

This video has been carefully designed to create a strong natural hallucination based on the motion aftereffect illusion (MAE). Use full screen and HD for better results.