The Miracle Mountain Riddle
A hiker climbs all day up a steep mountain path and arrives at the mountain top where he camps overnight. The next day he begins the descent down the same trail to the bottom of the mountain when suddenly he looks at his watch and exclaims, "That is amazing! I was at this very same spot at exactly the same time of day yesterday on my way up."
What is the probability that a hiker will be at exactly the same spot on the mountain at the same time of day on his return trip, as he was on the previous day's hike up the mountain?
Is the probability closest to (A) 99% or (B) 50% or (C) 0.1% ?
What is the probability that a hiker will be at exactly the same spot on the mountain at the same time of day on his return trip, as he was on the previous day's hike up the mountain?
Is the probability closest to (A) 99% or (B) 50% or (C) 0.1% ?
Hint: This is not a trick. His watch works perfectly well. He does not sit in the same spot all day or any other such device, although it would not change the answer if he did!
The answer is (A). Since it must happen, the probability is actually 1 (100%).
Explanation: Firstly, consider 2 men, one starting from the top of the mountain and hiking down while the other starts at the bottom and hikes up. At some time in the day, they will cross over. In other words they will be at the same place at the same time of day.
Now consider our man who has walked up on one day and begins the descent the next day. Imagine there is someone (a second person) shadowing his exact movements from the day before. When he meets his shadower (it must happen) it will be the exact place that he was the day before, and of course they are both at this spot at the same time.
Contrary to our common sense, which seems to say that this is an extremely unlikely event, it is a certainty.
NOTE: There is one unlikely event here, and that is that he will notice the time when he is at the correct location on both days, but that was not what the question asked. Did you answer this riddle correctly?
YES NO
Explanation: Firstly, consider 2 men, one starting from the top of the mountain and hiking down while the other starts at the bottom and hikes up. At some time in the day, they will cross over. In other words they will be at the same place at the same time of day.
Now consider our man who has walked up on one day and begins the descent the next day. Imagine there is someone (a second person) shadowing his exact movements from the day before. When he meets his shadower (it must happen) it will be the exact place that he was the day before, and of course they are both at this spot at the same time.
Contrary to our common sense, which seems to say that this is an extremely unlikely event, it is a certainty.
NOTE: There is one unlikely event here, and that is that he will notice the time when he is at the correct location on both days, but that was not what the question asked. Did you answer this riddle correctly?
YES NO
100 Blank Cards Riddle
Someone offers you the following deal:
There is a deck of 100 initially blank cards. The dealer is allowed to write ANY positive integer, one per card, leaving none blank. You are then asked to turn over as many cards as you wish. If the last card you turn over is the highest in the deck, you win; otherwise, you lose.
Winning grants you $50, and losing costs you only the $10 you paid to play.
Would you accept this challenge?
There is a deck of 100 initially blank cards. The dealer is allowed to write ANY positive integer, one per card, leaving none blank. You are then asked to turn over as many cards as you wish. If the last card you turn over is the highest in the deck, you win; otherwise, you lose.
Winning grants you $50, and losing costs you only the $10 you paid to play.
Would you accept this challenge?
Hint: Perhaps thinking in terms of one deck is the wrong approach.
Yes!
A sample strategy:
Divide the deck in half and turn over all lower 50 cards, setting aside the highest number you find. Then turn over the other 50 cards, one by one, until you reach a number that is higher than the card you set aside: this is your chosen "high card."
Now, there is a 50% chance that the highest card is contained in the top 50 cards (it is or it isn't), and a 50% chance that the second-highest card is contained in the lower 50. Combining the probabilities, you have a 25% chance of constructing the above situation (in which you win every time).
This means that you'll lose three out of four games, but for every four games played, you pay $40 while you win one game and $50. Your net profit every four games is $10.
Obviously, you have to have at least $40 to start in order to apply this strategy effectively. Did you answer this riddle correctly?
YES NO
A sample strategy:
Divide the deck in half and turn over all lower 50 cards, setting aside the highest number you find. Then turn over the other 50 cards, one by one, until you reach a number that is higher than the card you set aside: this is your chosen "high card."
Now, there is a 50% chance that the highest card is contained in the top 50 cards (it is or it isn't), and a 50% chance that the second-highest card is contained in the lower 50. Combining the probabilities, you have a 25% chance of constructing the above situation (in which you win every time).
This means that you'll lose three out of four games, but for every four games played, you pay $40 while you win one game and $50. Your net profit every four games is $10.
Obviously, you have to have at least $40 to start in order to apply this strategy effectively. Did you answer this riddle correctly?
YES NO
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
An Absentminded Philosopher Riddle
An absentminded philosopher forgot to wind up the only clock in his house. He had no radio, television, telephone, internet, or any other means of ascertaining the time. He therefore decided to travel by foot to his friend's house, a few miles down a straight desert road. He stayed there for the night and when he came back home the following morning, he was able to set his clock to the correct time. Assuming the philosopher always walks at the same speed, how did he know the exact time upon his return? Note: this is not a trick question. The Philosopher did not bring anything to his friend's house, nor did he bring anything back with him on his trip home.
Hint: We can assume that the journey to his friend's and back took exactly the same amount of time.
He Philosopher winds the grandfather clock to a random time right before leaving, 9:00 for example. Although this is not the right time, the clock can now be used to measure elapsed time. As soon as he arrives at his friend's house, the Philosopher looks at the time on his friend's clock. Let's say the time is 7:15. He stays overnight and then, before leaving in the morning, he looks at the clock one more time. Let's say the time is now 10:15 (15 hours later). When the Philosopher arrives home, he looks at his grandfather clock. Let's say his clock reads 12:40. By subtracting the time he set it to when he left (9:00) from the current time (12:40) he knows that he has been gone for 15 hours and 40 minutes. He knows that he spent 15 hours at his friends house, so that means he spent 40 minutes walking. Since he walked at the same speed both ways, it took him 20 minutes to walk from his friend's home back to his place. So the correct time to set the clock to in this example would therefore be 10:15 (the time he left his friend's house) + 20 minutes (the time it took him to walk home) = 10:35. Did you answer this riddle correctly?
YES NO
YES NO
Finding The Dough
Hint:
Losing His House Riddle
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Hamburger Race Riddle
Hint:
The Last Burger
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Weight Loss Frog Riddle
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The Future Of Trees Riddle
Hint:
Kidnapping The Queens Son
The Queen lives in a beautiful castle with her only son and a sheep-dog named Sir FooFoo. One day the Queen decides to go out for a spot of tea with some friends. She leaves her eight-year-old son in the care of her trusted servants. The 18 servants are: Harold the health instructor, Griffith the gardener, Tiffany the private tutor, Philip the photographer, Magdalina the maid, Boris the Butler, Geraldo the groundskeeper, Bernadette the barber, Sandy the sweeper, Anastasia the accountant, Constantine the carpenter, Joel the jester, Lucy the launderer, Sadie the seamstress, McKenzie the musical instructor, Lawrence the lawyer, Dorothy the dentist, Devon the doctor, and Surlamina the Secretary of State. When the Queen came home she discovered her son was missing and that he was kidnapped. The Queen came to a conclusion that it must've been one of her servants who kidnapped her son because he was too young to leave on his own and Sir FooFoo was harmless. The Queen interviewed all of her servants to see which one was responsible for the kidnapping. The alibis are as follows: Harold was lifting weights, Griffith was planting roses, Tiffany was checking homework, Philip was taking pictures of the botanical garden, Magdalina was making the beds, Boris was cleaning the banisters, Geraldo was supervising Griffith , Bernadette was trimming Sir FooFoo's hair, Sandy was sweeping in the corners, Anastasia was managing the Queen's affairs, Constantine was building a birdhouse, Joel was coming up with the jokes, Lucy was doing the laundry, Sadie was designing a dress for the Queen, McKenzie was playing the flute, Lawrence was suing the bank, Dorothy was preparing to extract the Queen's tooth when the Queen came home, Devon was examining an x-ray of the Queen's arm, and Surlamina was being a Secretary of State.
Who is the kidnapper?
Who is the kidnapper?
Hint:
Surlamina is responsible for the kidnapping because there is no Secretary of State in a monarchy. It is believed that Surlamina kidnapped the Queen's son because she was not given a real job. Did you answer this riddle correctly?
YES NO
YES NO
Hot Air Balloon Over The Sahara
One sunny afternoon, three men go for a ride on a hot air balloon over the Sahara desert. An hour into the trip, the balloon begins to lose altitude. A month later, someone found one of the ballooners laying on the desert sand dead, naked, and holding half a toothpick. What happened to him?
Hint:
As the balloon lost altitude, the men took of their clothes and threw them overboard to decrease the weight of the balloon. The balloon continued to drop so the men drew straws to see who would be forced to jump. The dead man in the desert drew the shortest one (the half toothpick). Did you answer this riddle correctly?
YES NO
YES NO
The Perfect Man And An Alien Riddle
A woman, and the perfect man and an alien get into a car crash. only one survives. who survives explain.
Hint:
The woman. There is no such thing as the perfect man or aliens. Did you answer this riddle correctly?
YES NO
YES NO
Can You Solve The Horse Sale Brain Teaser?
A man buys a horse for $60, then sells it for $70. He buys the horse back for $80, and then sells the horse for $90.
How much money did he make or lose?
Did he break even?
How much money did he make or lose?
Did he break even?
Hint: He didn't break even.
This Countrys Capital Is Canberra
This countrys capital is Canberra
You might go to Bondi Beach to surf
Go diving at the Great Barrier Reef
And explore Melbourne, Sydney or Perth
What country is this?
You might go to Bondi Beach to surf
Go diving at the Great Barrier Reef
And explore Melbourne, Sydney or Perth
What country is this?
Hint:
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