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
Three People In A Room
Three people enter a room and have a green or blue hat placed on their head. They cannot see their own hat, but can see the other hats.
The color of each hat is purely random. They could all be green, or blue, or any combination of green and blue.
They need to guess their own hat color by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $50,000 each, but if anyone guess incorrectly they all get nothing.
What is the best strategy?
The color of each hat is purely random. They could all be green, or blue, or any combination of green and blue.
They need to guess their own hat color by writing it on a piece of paper, or they can write 'pass'.
They cannot communicate with each other in any way once the game starts. But they can have a strategy meeting before the game.
If at least one of them guesses correctly they win $50,000 each, but if anyone guess incorrectly they all get nothing.
What is the best strategy?
Hint:
Simple strategy: Elect one person to be the guesser, the other two pass. The guesser chooses randomly 'green' or 'blue'. This gives them a 50% chance of winning.
Better strategy: If you see two blue or two green hats, then write down the opposite color, otherwise write down 'pass'.
It works like this ('-' means 'pass'):
Hats: GGG, Guess: BBB, Result: Lose
Hats: GGB, Guess: --B, Result: Win
Hats: GBG, Guess: -B-, Result: Win
Hats: GBB, Guess: G--, Result: Win
Hats: BGG, Guess: B--, Result: Win
Hats: BGB, Guess: -G-, Result: Win
Hats: BBG, Guess: --G, Result: Win
Hats: BBB, Guess: GGG, Result: Lose
Result: 75% chance of winning! Did you answer this riddle correctly?
YES NO
Better strategy: If you see two blue or two green hats, then write down the opposite color, otherwise write down 'pass'.
It works like this ('-' means 'pass'):
Hats: GGG, Guess: BBB, Result: Lose
Hats: GGB, Guess: --B, Result: Win
Hats: GBG, Guess: -B-, Result: Win
Hats: GBB, Guess: G--, Result: Win
Hats: BGG, Guess: B--, Result: Win
Hats: BGB, Guess: -G-, Result: Win
Hats: BBG, Guess: --G, Result: Win
Hats: BBB, Guess: GGG, Result: Lose
Result: 75% chance of winning! Did you answer this riddle correctly?
YES NO
The Tenth Floor Elevator Riddle
A man lives on the tenth floor of a building. Every day he takes the elevator to go down to the ground floor to go to work. When he returns he takes the same elevator to the seventh floor and walks up the stairs to reach his apartment on the tenth floor. He hates walking so why does he do it?
Note that there is nothing wrong with the elevator or the design of the building. It's a perfectly normal elevator in a perfectly normal building.
Note that there is nothing wrong with the elevator or the design of the building. It's a perfectly normal elevator in a perfectly normal building.
Hint: The elevator is perfectly normal and the design of the building is perfectly normal, but there is something different about the man.
The man is very short (i.e. a little person).
Because of his short stature, the man is unable to reach any higher than the button for the 7th floor (elevator floor number buttons are laid out in descending floor order from top to bottom). Did you answer this riddle correctly?
YES NO
Because of his short stature, the man is unable to reach any higher than the button for the 7th floor (elevator floor number buttons are laid out in descending floor order from top to bottom). Did you answer this riddle correctly?
YES NO
The 30th Floor Office Riddle
This guys office is on the 30th floor of the building. Everyday,he gets off at the 25th floor and walks the extra 5 floors up stairs. Why does he walk the extra 5 floors rather then taking the elevator?
Hint:
He is a midget. He is to small to reach any higher then the 25 button! Did you answer this riddle correctly?
YES NO
YES NO
Ransack My Stash
Hint:
Fruit Shopping
I am at the local super-market buying fruits. An apple costs $1. An orange costs $9 more than the apple. A watermelon costs $5 more than the orange. If I buy one of each of these 3, what is the total amount I have to pay?
Hint:
$26
The cost of an apple is $1. Since it is mentioned that the orange is $9 more than the apple.
Cost of orange = $10; So cost of watermelon = $15
So if I buy all 3 the total I have to pay is; 1 + 10 + 15 = $26 Did you answer this riddle correctly?
YES NO
The cost of an apple is $1. Since it is mentioned that the orange is $9 more than the apple.
Cost of orange = $10; So cost of watermelon = $15
So if I buy all 3 the total I have to pay is; 1 + 10 + 15 = $26 Did you answer this riddle correctly?
YES NO
100 Fruits
For $1 you get 40 Cherries. For $3 you get 1 Orange. For $5 you get 1 Watermelon. Your mother told you to get 100 fruits for $100. How many of Cherries, Oranges and Watermelons will you buy?
Hint:
See A Doctor Or A Nurse
And then you feel even worse
You might go to this building
To see a doctor or a nurse
Where is this building?
Hint:
Seen A Lot On Valentines Day
I smell nice but Im not perfume
I get put in water but Im not dirty clothing
I have a stem but Im not a wine glass
I get seen a lot on Valentines Day but Im not a stuffed animal
Do you know what I am?
Hint:
It's Valentines Day
These flowers can be yellow
And sometimes orange, pink or white
But when its Valentines Day
Giving a red one is most right
What are these flowers?
And sometimes orange, pink or white
But when its Valentines Day
Giving a red one is most right
What are these flowers?
Hint:
Am Room With Windows Riddle
In a room with four walls no windows. On the south wall there is a door and on the north too. There is a table in the middle with four chairs. On the table there are 52 bicycles and three empty boxes in one of the chairs there is a dead man. How did he die?
Hint:
How he died was he was in a submarine and they were at war with another country and their ship was hit there were four people in there. The bicycles are actually playing card brands and there were three oxygen tanks. the four men bet with cards to see who would get to take one oxygen tank. obviously the man who was dead lost and he was the one who died from lack of oxygen in the sub. Did you answer this riddle correctly?
YES NO
YES NO
Monster Cookies Riddle
If a monster has 13 giant chocolate chip Halloween cookies in one hand and 10 super large orange covered Halloween cookies in the other, what do you have?
Hint:
Baubles On Your Tree
Hint:
Escape Plan Riddle
Hint: The answer involves word play.
You look in the mirror and see what you saw. You take the saw and cut it in half. Two halves make a whole. Put the hole on the wall and climb out. Did you answer this riddle correctly?
YES NO
YES NO
Not A Melon Riddle
I am a type of citrus fruit
Although I am not an orange
I am not a melon either
But melon you should rearrange
What am I?
Although I am not an orange
I am not a melon either
But melon you should rearrange
What am I?
Hint:
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