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
Sometimes Yellow Riddle
I follow a route but I'm not a mailman
I'm red in London but I'm not a telephone box
I'm sometimes yellow in the US but I'm not a taxi
I'm a mode of transport but I'm not a train
I have wheels that go round and round but I'm not a car
I'm red in London but I'm not a telephone box
I'm sometimes yellow in the US but I'm not a taxi
I'm a mode of transport but I'm not a train
I have wheels that go round and round but I'm not a car
Hint:
Strive With Wind And Wave Riddle
Off I must strive with wind and wave, battle them both
when under the sea.
I feel out the bottom, a foreign land. In lying still, I am
Strong in the strife;
If I fail in that, they are stronger than I, and
Wrenching me loose, soon put me to rout.
They wish to capture what I must keep. I can master
Them both if my grip holds out,
If the rocks bring succor and lend support, strength
In the struggle. Ask my name
when under the sea.
I feel out the bottom, a foreign land. In lying still, I am
Strong in the strife;
If I fail in that, they are stronger than I, and
Wrenching me loose, soon put me to rout.
They wish to capture what I must keep. I can master
Them both if my grip holds out,
If the rocks bring succor and lend support, strength
In the struggle. Ask my name
Hint:
1 Rabbit Saw 6 Elephants Riddle
1 rabbit saw 6 elephants while going to the river.
Every elephant saw 2 monkeys going towards the river.
Every monkey holds 1 parrot in their hands.
How many Animals are going towards the river?
Every elephant saw 2 monkeys going towards the river.
Every monkey holds 1 parrot in their hands.
How many Animals are going towards the river?
Hint:
5 Animals.
Lets go through the question again.
1 rabbit saw 6 elephants while going to the river. Hence, 1 animal (rabbit) is going towards the river.
Every elephant saw 2 monkeys going towards the river. This is the tricky part, from the sentence it seems to imply each of the 6 elephants saw 2 monkeys going towards the river, hence logically will be 6 x 2 = 12 animals (monkeys) going towards the river.
However, the statement does not explicitly mention that Every elephant saw 2 DIFFERENT monkeys, hence implicit rules apply and infer that the 2 monkeys are the same.
Hence, correct answer is that every elephant saw 2 monkeys, and by inference, the 2 monkeys are the same, hence there exists only 2 monkeys which are going towards the river !!
Finally, every monkey holds 1 parrot in their hands. Hence, 2 parrots are going towards the river.
So in total, 1 rabbit, 2 monkeys and 2 parrots (5 animals) are going towards the river. Did you answer this riddle correctly?
YES NO
Lets go through the question again.
1 rabbit saw 6 elephants while going to the river. Hence, 1 animal (rabbit) is going towards the river.
Every elephant saw 2 monkeys going towards the river. This is the tricky part, from the sentence it seems to imply each of the 6 elephants saw 2 monkeys going towards the river, hence logically will be 6 x 2 = 12 animals (monkeys) going towards the river.
However, the statement does not explicitly mention that Every elephant saw 2 DIFFERENT monkeys, hence implicit rules apply and infer that the 2 monkeys are the same.
Hence, correct answer is that every elephant saw 2 monkeys, and by inference, the 2 monkeys are the same, hence there exists only 2 monkeys which are going towards the river !!
Finally, every monkey holds 1 parrot in their hands. Hence, 2 parrots are going towards the river.
So in total, 1 rabbit, 2 monkeys and 2 parrots (5 animals) are going towards the river. Did you answer this riddle correctly?
YES NO
What Will You Open First Riddle
You stay alone and you are sleeping in your room when your friends are ringing the doorbell. They've come to have breakfast with you and all you have at home is a box of cornflakes, Bread, Jam and one carton of Milk. What will you open first?
Hint:
Trace Your Steps Back Riddle
Trace your steps back. Find chunks of me. Do try to be smart. I go on forever, but the last safe holds my start. What am I?
Hint:
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