#### Trending Tags

#### Popular Searches

10 Ft Rope Ladder Hangs Over The Riddles 6every Evening I Get Myignment Riddles Breast Riddles Can You Name A Colour Without E Riddles Fire Pit Riddles Five Legs One Eye Four Tails Five Ears Three Heads Riddles I Right I Riddles In A Church There Are 5 Candles At Night 3 Thieves And 2 Thieves Enter Only Thieves Riddlesieves Riddles Marriage P Riddles The Rain In Spain Riddles What Falls But Never Breaks What Breaks But Never Falls Riddles What Is The Shortest Month In The Year Rid Riddles When You Have Me You Feel Like Sharing Me But If You Do Share Me You Wont Have Me What Am I Riddles Which Hand Is It Better To Writhe With Riddles Why Are Cookies Called Cookies Whe Riddles

Feel free to use content on this page for your website or blog, we only ask that you reference content back to us. Use the following code to link this page:

Terms · Privacy · Contact
Riddles and Answers © 2019

## 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.

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

## Add Your Riddle Here

Have some tricky riddles of your own? Leave them below for our users to try and solve.