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
Name A Word Riddle
Hint:
20 Apples Riddle
There are 20 people in an empty, square room. Each person has full sight of the entire room and everyone in it without turning his head or body, or moving in any way (other than the eyes). Where can you place an apple so that all but one person can see it?
Hint:
The Smuggler Riddle
Every day, a man crosses the border of Mexico on a bicycle with two bags of sand. The customs officers check his bags and they are full of sand. The custom officers are aware that he is smuggling something but are not sure what is it exactly. As they do not have any evidence, they let him cross the border. What is he smuggling?
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
Pick A Room Riddle
It is Halloween and your friends dare you to go into a haunted house. You creep up to the door, a little scared wondering what is behind the door. You go in and there is a long hallway leading out into a dark musty room with three doors.
You're kind of scared once you are inside. You try to turn back, to get back outside, but when you turn around the door is closed and locked. You yell for help but there is only silence. The room is dark and you look for a light source. You see a light switch and try to turn it on. Sadly the power is out. You are terrified but have no choice but to follow the long hallway to the three doors in the pitch black.
Behind one door is a bottomless pit with no end. Behind another door is an electric chair which you must sit in. Behind the last door is a pool full of acid. You must go in one of the rooms to the danger. Which one should you go through?
You're kind of scared once you are inside. You try to turn back, to get back outside, but when you turn around the door is closed and locked. You yell for help but there is only silence. The room is dark and you look for a light source. You see a light switch and try to turn it on. Sadly the power is out. You are terrified but have no choice but to follow the long hallway to the three doors in the pitch black.
Behind one door is a bottomless pit with no end. Behind another door is an electric chair which you must sit in. Behind the last door is a pool full of acid. You must go in one of the rooms to the danger. Which one should you go through?
Hint:
You should definitely go through the electric chair. Since the power is out, when you sit in the electric chair it will have no effect on you. Did you answer this riddle correctly?
YES NO
YES NO
Savor The Flavor Riddle
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, I'm best enjoyed among pleasant company.
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; I'll send you back refreshed and full of energy.
What am I?
A necessity to some, a treasure to many, I'm best enjoyed among pleasant company.
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; I'll send you back refreshed and full of energy.
What am I?
Hint: This doesn't need a hint, but in case you peeked: I'll have a grande latte!
Coffee. It was first discovered in the area of Africa now called Ethiopia. Legend has it that a goat herder observed his goats acting unusually frisky after eating berries from a bush. When he tried them himself, his energy was renewed. And the rest is history. Did you answer this riddle correctly?
YES NO
YES NO
Coffee Diner Riddle
A man walks into a diner and sits down. There's a new waitress working that he's never seen before. When she comes to his table to take his order, he says "Just a cup of coffee please." A few minutes later the waitress brings the man his coffee and heads back to the kitchen. A short while later, the man notices that there is a fly in his coffee and calls the waitress back. He asks her nicely to bring him another cup. The waitress brings the man's cup of coffee back to the kitchen and returns a few moments later. "Here you are, I poured you a new cup of coffee, no fly this time" she says and hands him the cup. The waitress turns around and starts to head back to the kitchen. She only takes a few steps before she hears the man shout out "Hey, this is the same cup of coffee, all you did was remove the fly!"
Assuming the coffee was still hot, how did the man know it was the same cup of coffee?
Assuming the coffee was still hot, how did the man know it was the same cup of coffee?
Hint: A man walks into a diner and sits down. There's a new waitress working that he's never seen before. When she comes to his table to take his order, he says "Just a cup of coffee please." A few minutes later the waitress brings the man his coffee and heads
Because the coffee was sweet. The man had added sugar to his coffee before noticing the fly. When the waitress brought him the "new" cup of coffee, he took a sip (to check whether it was in fact a newly poured cup of coffee) and noticed that the coffee was "already" sweet. Did you answer this riddle correctly?
YES NO
YES NO
Farmer Joe's Container Riddle
Farmer Joe was cleaning out his big old dusty farm shed. He dragged out an old water container which was full of old dirty water and it weighed 5 kilograms. Joe put something in the container and then it weighed less. What did he put in the container?
Hint:
Smoking Girlfriend Riddle
Hint:
The Locked Away Princess Riddle
A princess was locked in a tower with four yards of pure brick for the ceiling, floors, and walls. There were no windows or doors at all, no way to get out.
She turned the knob to take a bath. When she notices the tub getting full, she tried to turn the knob, but it's stuck!
How does she avoid drowning?
She turned the knob to take a bath. When she notices the tub getting full, she tried to turn the knob, but it's stuck!
How does she avoid drowning?
Hint:
I Have A Source Riddle
I have a source but Im not a journalist
I have a delta but Im not a Greek alphabet
I have banks on both sides of me but Im not surrounded by money
I flow but Im not a bloodstream
Im full of water but Im not a fish tank
What am I?
I have a delta but Im not a Greek alphabet
I have banks on both sides of me but Im not surrounded by money
I flow but Im not a bloodstream
Im full of water but Im not a fish tank
What am I?
Hint:
21 Jars Riddle
You have 21 jars with you. Out of them, 7 are filled with water, 7 are half-full with water and 7 are empty. How will you distribute the jars among three people such that each one of them gets the equal number of jars and equal amount of water?
Hint:
Give 3 full, 1 half-full and 3 empty bottles to the first person.
Give 3 full, 1 half-full and 3 empty bottles to the second person.
Give 1 full, 5 half-full and 1 empty bottle to the third person. Did you answer this riddle correctly?
YES NO
Give 3 full, 1 half-full and 3 empty bottles to the second person.
Give 1 full, 5 half-full and 1 empty bottle to the third person. Did you answer this riddle correctly?
YES NO
Debbie Driver Riddle
Debbie starts driving her dragster from rest and constantly accelerates to 60 mph in 10 seconds. How far does she travel in those 10 seconds?
Hint:
The Homicide Team Riddle
A homicide team enters a crime scene where a dead body of a fat old man lies there on the floor with blood oozing out of his head. The victim is holding a gun and a tape recorder lies there by his side. One of the detective picks up the recorder and plays it "I am tired of this life and hence I have decided to relieve myself from the worldly pains". A gunshot follows the message.
The teams starts investigating a murder investigation.
Why?
The teams starts investigating a murder investigation.
Why?
Hint:
If the man killed himself, he would not have been able to rewind the cassette. Thus it is clear someone else killed him. Did you answer this riddle correctly?
YES NO
YES NO
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