The 100 Seat Airplane
People are waiting in line to board a 100-seat airplane. Steve is the first person in the line. He gets on the plane but suddenly can't remember what his seat number is, so he picks a seat at random. After that, each person who gets on the plane sits in their assigned seat if it's available, otherwise they will choose an open seat at random to sit in.
The flight is full and you are last in line. What is the probability that you get to sit in your assigned seat?
The flight is full and you are last in line. What is the probability that you get to sit in your assigned seat?
Hint: You don't need to use complex math to solve this riddle. Consider these two questions:
What happens if somebody sits in your seat?
What happens if somebody sits in Steve's assigned seat?
The correct answer is 1/2.
The chase that the first person in line takes your seat is equal to the chance that he takes his own seat. If he takes his own seat initially then you have a 100% chance of sitting in your seat, if he takes your seat you have a 0 percent chance. Now after the first person has picked a seat, the second person will enter the plan and, if the first person has sat in his seat, he will pick randomly, and again, the chance that he picks your seat is equal to the chance he picks someone your seat. The motion will continue until someone sits in the first persons seat, at this point the remaining people standing in line which each be able to sit in their own seats. Well how does that probability look in equation form? (2/100) * 50% + (98/100) * ( (2/98) * 50% + (96/98) * ( (2/96) * (50%) +... (2/2) * (50%) ) ) This expansion reduces to 1/2.
An easy way to see this is trying the problem with a 3 or 4 person scenario (pretend its a car). Both scenarios have probabilities of 1/2. Did you answer this riddle correctly?
YES NO
The chase that the first person in line takes your seat is equal to the chance that he takes his own seat. If he takes his own seat initially then you have a 100% chance of sitting in your seat, if he takes your seat you have a 0 percent chance. Now after the first person has picked a seat, the second person will enter the plan and, if the first person has sat in his seat, he will pick randomly, and again, the chance that he picks your seat is equal to the chance he picks someone your seat. The motion will continue until someone sits in the first persons seat, at this point the remaining people standing in line which each be able to sit in their own seats. Well how does that probability look in equation form? (2/100) * 50% + (98/100) * ( (2/98) * 50% + (96/98) * ( (2/96) * (50%) +... (2/2) * (50%) ) ) This expansion reduces to 1/2.
An easy way to see this is trying the problem with a 3 or 4 person scenario (pretend its a car). Both scenarios have probabilities of 1/2. Did you answer this riddle correctly?
YES NO
A Room With Plenty Of Space
Hint:
Flip The Switch Riddle
There is a prison with 100 prisoners, each in separate cells with no form of contact. There is an area in the prison with a single light bulb in it. Each day, the warden picks one of the prisoners at random, even if they have been picked before, and takes them out to the lobby. The prisoner will have the choice to flip the switch if they want. The light bulb starts off.
When a prisoner is taken into the area with the light bulb, he can also say "Every prisoner has been brought to the light bulb." If this is true all prisoners will go free. However, if a prisoner chooses to say this and it's wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure.
Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves.
What strategy could they use to ensure they will go free?
When a prisoner is taken into the area with the light bulb, he can also say "Every prisoner has been brought to the light bulb." If this is true all prisoners will go free. However, if a prisoner chooses to say this and it's wrong, all the prisoners will be executed. So a prisoner should only say this if he knows it is true for sure.
Before the first day of this process begins, all the prisoners are allowed to get together to discuss a strategy to eventually save themselves.
What strategy could they use to ensure they will go free?
Hint:
Only allow one prisoner to turn the light bulb off and all of the others turn it on if they have never turned it on before. If they have turned it on before they do nothing. The prisoner that can turn it off then knows they have all been there and saves them all when he has turned it off 99 times. Did you answer this riddle correctly?
YES NO
YES NO
Common Letters Riddle
Hint:
Buttons, Scarf And A Carrot Riddle
If you go outside, in the summer, and see 3 buttons, a scarf and a carrot. Nobody put them there, yet there they lay. If no one put them down, what are they?
Hint:
A Cool Treat Riddle
Hint:
Melting In The Sun Riddle
You might love me in summer but I never like the sun. The hotter the weather, the softer I get. What am I?
Hint:
Refreshed And Full Of Energy
Discovered in Africa, I spread like a tide, to become a hot staple known the world wide. A necessity to some, a treasure to many, Im best enjoyed among pleasant company. Some like me hot and some like me cold. Some prefer mild, others only bold. Some take me straight, while some like to savor my essence to which has been added a flavor. So put down your cares and sit awhile with me; Ill send you back refreshed and full of energy. What am I?
Hint:
Coins In My Wallet Riddle
I have 100 coins in my wallet.
What is the minimum number of coin(s), I would be required in order to make sure each coin touched exactly three other coins.
What is the minimum number of coin(s), I would be required in order to make sure each coin touched exactly three other coins.
Hint:
4
3 placed flat on the table in a triangle(touching each other) and put the fourth one on top of them in the middle. Did you answer this riddle correctly?
YES NO
3 placed flat on the table in a triangle(touching each other) and put the fourth one on top of them in the middle. Did you answer this riddle correctly?
YES NO
The Fastest Runner Riddle
Hint:
Odd Number Becomes Even
Can you solve this classic number riddle before getting hung?
Hint: Spell the number out.
Sumer House Riddle
Hint:
Roman Numeral IX Riddle
Hint:
You'll See Me Riddle
Youll see me when the sun is high and also late at night,
Im in the songs of holidays, when the snow is white,
Kings and Queens and royalty, are all found in me,
Im the largest of them all, with just one you see,
Step by step with pounding feet, Im tribes of angry men,
Im above your hands right now, for help or to go again,
Youll use me in the kitchen, or add a little more,
Ill be in the years to come, and the days of yore.
What am I?
Im in the songs of holidays, when the snow is white,
Kings and Queens and royalty, are all found in me,
Im the largest of them all, with just one you see,
Step by step with pounding feet, Im tribes of angry men,
Im above your hands right now, for help or to go again,
Youll use me in the kitchen, or add a little more,
Ill be in the years to come, and the days of yore.
What am I?
Hint:
The Number Twelve (12).
Noon and midnight are both 12 oclock and the Twelve Days of Christmas is a popular Christmas carol.
There are twelve face cards in a standard 52-card deck and twelve is the largest number with one syllable.
There are twelve steps in Alcoholics Anonymous, a troy pound is 12 ounces, there were 12 tribes of Israel and a popular movie was called, Twelve Angry Men (12 members of the jury). There are twelve function keys on your keyboard. F1 often shows a help screen and F5 reloads pages in your browser.
Many recipes measure items by the dozen, adding one more for a bakers dozen. There are twelve months in a year.
Did you answer this riddle correctly?
YES NO
Noon and midnight are both 12 oclock and the Twelve Days of Christmas is a popular Christmas carol.
There are twelve face cards in a standard 52-card deck and twelve is the largest number with one syllable.
There are twelve steps in Alcoholics Anonymous, a troy pound is 12 ounces, there were 12 tribes of Israel and a popular movie was called, Twelve Angry Men (12 members of the jury). There are twelve function keys on your keyboard. F1 often shows a help screen and F5 reloads pages in your browser.
Many recipes measure items by the dozen, adding one more for a bakers dozen. There are twelve months in a year.
Did you answer this riddle correctly?
YES NO
Making Ten Riddle
Hint:
Yes it is possible in Roman Numerals. In Roman Numerals,
9 = IX
10 = X
11 = XI
Thus by removing one from 9, you are getting 10 and by removing one from 11, you are getting 10 again. Did you answer this riddle correctly?
YES NO
9 = IX
10 = X
11 = XI
Thus by removing one from 9, you are getting 10 and by removing one from 11, you are getting 10 again. Did you answer this riddle correctly?
YES NO
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