The Secret Santa Exchange
A group of ten friends decide to exchange gifts as secret Santas. Each person writes his or her name on a piece of paper and puts it in a hat. Then each person randomly draws a name from the hat to determine who has him as his or her secret Santa. The secret Santa then makes a gift for the person whose name he drew.
When it's time to exchange presents, each person walks over to the person he made the gift for and holds his or her left hand in his right hand.
What is the probability that the 10 friends holding hands form a single continuous circle?
When it's time to exchange presents, each person walks over to the person he made the gift for and holds his or her left hand in his right hand.
What is the probability that the 10 friends holding hands form a single continuous circle?
Hint: It's not as difficult as it seems.
It's the number of ways the friends can form a circle divided by the number of ways the names can be drawn out of the hat.
1/10
For a group of n friends, there are n! (n factorial) ways to draw the names out of the hat. Since a circle does not have a beginning and end, choose one person as the beginning and end of the circle. There are now (n-1)! ways to distribute the remaining people around the circle. Thus the probability of forming a single circle is
(n-1)! / n!
Since n! = (n-1)! * n (for n > 1), this can be rewritten as
(n-1)! / (n*(n-1)!)
Factoring out the (n-1)! from the numerator and denominator leaves
1/n
as the probability. Did you answer this riddle correctly?
YES NO
For a group of n friends, there are n! (n factorial) ways to draw the names out of the hat. Since a circle does not have a beginning and end, choose one person as the beginning and end of the circle. There are now (n-1)! ways to distribute the remaining people around the circle. Thus the probability of forming a single circle is
(n-1)! / n!
Since n! = (n-1)! * n (for n > 1), this can be rewritten as
(n-1)! / (n*(n-1)!)
Factoring out the (n-1)! from the numerator and denominator leaves
1/n
as the probability. Did you answer this riddle correctly?
YES NO
A Town With No Houses
Hint:
A 10 Foot Rope Ladder
A 10 foot rope ladder hangs over the side of a boat with the bottom rung on the surface of the water. The rungs are one foot apart, and the tide goes up at the rate of 6 inches per hour. How long will it be until three rungs are covered?
Hint:
Laying An Egg Riddle
Hint:
It didn't roll since when did roosters start laying eggs? Did you answer this riddle correctly?
YES NO
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
A 7 Foot Clown Riddle
A 7 foot clown stood up and held a water glass over his head. He accidentally dropped the glass, but nothing spilled. How is this possible?
Hint:
Known To Cause A Rush
I'm sometimes found in a pot but I'm not stew
I can be a bar but Im not soap
I've been known to cause a rush but Im not a Black Friday sale
Im a type of metal but Im not tin
I can be a medal but Im not silver
I am?
I can be a bar but Im not soap
I've been known to cause a rush but Im not a Black Friday sale
Im a type of metal but Im not tin
I can be a medal but Im not silver
I am?
Hint:
Cities But No Houses Riddle
It has cities but no houses, it has oceans but no water, it has forests but no trees, it has deserts but no sand. What is it?
Hint:
A Ship Drops This To Stay Still
A ship drops this to stay still
Even if the waters calm
It is also a tattoo
You can see on Popeyes arm
It has to be a?
Even if the waters calm
It is also a tattoo
You can see on Popeyes arm
It has to be a?
Hint:
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:
I'm A Country But Im Not Russia Riddle
Im a country but Im not Russia
Im in the southern hemisphere but Im not Argentina
Im popular with surfers but Im not South Africa
Im surrounded by water but Im not Madagascar
Im sometimes called Oz but I dont have anything to do with wizards
What am I?
Im in the southern hemisphere but Im not Argentina
Im popular with surfers but Im not South Africa
Im surrounded by water but Im not Madagascar
Im sometimes called Oz but I dont have anything to do with wizards
What am I?
Hint:
7B91011 Riddle
Ray Whitcombe was 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
Mr. Harold Nichols, Ray's best friend
All three visited Mr. Whitcombe the day of his murder, but all three provided 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?
Mrs. Barbara Whitcombe, Ray's wife
Mr. Jason McCubbins, Ray's business partner
Mr. Harold Nichols, Ray's best friend
All three visited Mr. Whitcombe the day of his murder, but all three provided 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 was the clue to solving this murder. The police realized that since Mr. Whitcombe was wearing his watch on his right arm, he must have been left-handed. 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
The calendar was the clue to solving this murder. The police realized that since Mr. Whitcombe was wearing his watch on his right arm, he must have been left-handed. 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
7 Ice Cubes Riddle
I have 7 ice cubes inside a cup of water how many ice cubes do I have left after putting the cup in the freezer?
Hint:
$100 Bill Grocery Store Thief
A guy walks into a store and steals a $100 bill from the register without the owners knowledge.
He then buys $70 worth of goods using the $100 bill and the owner gives $30 in change.
How much money did the owner lose?
$30, $70, $100, $130, $170, or $200?
He then buys $70 worth of goods using the $100 bill and the owner gives $30 in change.
How much money did the owner lose?
$30, $70, $100, $130, $170, or $200?
Hint:
The best answer from the choices is the owner lost $100. The $100 bill that was stolen was then given back to the owner. What the owner loses is the $70 worth of goods and the $30 in change, which makes for a total of $70 + $30 = $100. The owner has lost $100.
Technically, the owner lost $30 plus the value, V, of the $70 of goods. Since stores typically sell goods at a markup, the value may be less than $70. But in the case of a loss leader, the owner may have lost more than $70. Did you answer this riddle correctly?
YES NO
Technically, the owner lost $30 plus the value, V, of the $70 of goods. Since stores typically sell goods at a markup, the value may be less than $70. But in the case of a loss leader, the owner may have lost more than $70. Did you answer this riddle correctly?
YES NO
The Biggest Alphabet Riddle
Hint:
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