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
Annoying Or Tricky To Clean Up After Sex Riddle
Hint:
Serial Killer Pill Riddle
Here is a serial killer, who kidnaps people and asks them to take 1 of 2 pills. One pill is harmless, and the other one is poisonous. The mystery is: Whichever pill a victim takes, the serial killer takes the other one. But every time the killer survives and the victim is dead.
How is this possible? Why the killer always gets the harmless pill?
How is this possible? Why the killer always gets the harmless pill?
Hint:
The poison was in the glass of water the victim drank. Therefore every time he would survive. Did you answer this riddle correctly?
YES NO
YES NO
Secretes You Can Keep Riddle
Riddle me this
You write on me and secrets I can keep. In places never seen. I spin like a top. Though stiff as a board, I'm often described like a mop. What am I?
You write on me and secrets I can keep. In places never seen. I spin like a top. Though stiff as a board, I'm often described like a mop. What am I?
Hint:
In A Secret Spot
I'm in the big black pot. You can only take me, if you've found the secret spot. I'm worth a lot, you should know. The place I'm in, is at the end of the rainbow. What am I?
Hint:
The Serial Killer Husband
A man kills his wife. Many people watch him doing so. Yet no one will ever be able to accuse him of murder. Why?
Hint:
Safe And Secure Riddle
As a whole, I am both safe and secure.
Behead me, and I become a place of meeting.
Behead me again, and I am the partner of ready.
Restore me, and I become the domain of beasts.
What am I?
Behead me, and I become a place of meeting.
Behead me again, and I am the partner of ready.
Restore me, and I become the domain of beasts.
What am I?
Hint:
Figure Out The Sequence
Hint: Each number describes the previous number.
The next number it: 13112221. Each number describes the previous number. Starting with 1, the second line describes it 11 (one 1). Then the third line describes 11 as 21 (two 1's). Then the fourth line describes 21 as 1211 (one 2, one 1). This is the pattern. Did you answer this riddle correctly?
YES NO
YES NO
Seagulls In The Sea
Hint:
Because if they flew over the bay they would be called bagels! Did you answer this riddle correctly?
YES NO
YES NO
Trampoline Season
Hint:
Sex Of A Chromosome
Hint:
The Barber Of Seville
The Barber of Seville shaves all men living in Seville.
No man living in Seville is allowed to shave himself.
The Barber of Seville lives in Seville.
Who shaves the Barber of Seville?
No man living in Seville is allowed to shave himself.
The Barber of Seville lives in Seville.
Who shaves the Barber of Seville?
Hint:
Seconds In A Year Riddle
Hint:
The Red Sea Riddle
Hint:
The Black Sea Riddle
Hint:
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