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
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:
A Cat With 3 Kittens Riddle
Hint: Consider the punctuation.
No Living Cats On Mars Riddle
Hint:
Annoying Or Tricky To Clean Up After Sex Riddle
Hint:
The First Cat To Discover America Riddle
Hint:
A Cat Had Three Kittens
Hint: Consider the punctuation.
Cat Wins A Dog Show Riddle
Hint:
When Is It Bad Luck To See A Black Cat 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
The Dog Chased The Cat Riddle
Hint:
How Many Cats Can You Put In An Empty Box Riddle
Hint:
What Side Of A Cat Has The Most Fur Riddle
Hint:
Can You See The Cat Riddle
Hint:
The curve of the curtain and the outline of the woman's face and shoulder creates the outline of a cat. Did you answer this riddle correctly?
YES NO
YES NO
Square Room Cats Riddle
In a square room there is a cat in every corner of the room. In front of every cat there are 3 cats. How many cats are there altogether?
Hint:
So here in the principal explanation "In a square room there is a feline in each edge of the room" unmistakably the room is square and there is a feline in each edge of room.
As we as a whole realize that square has 4 corners so here there are 4 felines in each side of the room.
The second proclamation of the enigma says "before each feline there are 3 felines."
As we definitely know from the primary articulation that there are 4 felines in the room. So each and every feline in the room will have 3 felines before them. Did you answer this riddle correctly?
YES NO
As we as a whole realize that square has 4 corners so here there are 4 felines in each side of the room.
The second proclamation of the enigma says "before each feline there are 3 felines."
As we definitely know from the primary articulation that there are 4 felines in the room. So each and every feline in the room will have 3 felines before them. Did you answer this riddle correctly?
YES NO
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