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
Dark But Not A Room With Curtains
I'm sometimes dark but I'm not a room with curtains
I sometimes contain peanut butter but I'm not a sandwich
I'm sometimes melted but I'm not an ice cube
I'm sometimes in cookies but I'm not a raisin
I'm sometimes a bar but I'm not made of metal
I'm sometimes a chip but I'm not made of potato
What am I?
I sometimes contain peanut butter but I'm not a sandwich
I'm sometimes melted but I'm not an ice cube
I'm sometimes in cookies but I'm not a raisin
I'm sometimes a bar but I'm not made of metal
I'm sometimes a chip but I'm not made of potato
What am I?
Hint:
Browning Bread Riddle
When you feel hungry
Having just got out of bed
One item you may use
Is the thing that can brown bread?
Having just got out of bed
One item you may use
Is the thing that can brown bread?
Hint:
It Was Murder Riddle
A body is found at the bottom of a multistory building. Seeing the position of the body it is evident that the person jumped from one of the windows.
A homicide detective is called to look after the case. He goes to the first floor and walks in the room facing the direction in which the body was found. He opens the window in that direction and flips a coin towards the floor.
Then he goes to the second floor and repeats the process. He keeps on doing it till the last floor. Then, when he climbs down, he tells the team that it is a murder not suicide.
How did he come to know that it was a murder?
A homicide detective is called to look after the case. He goes to the first floor and walks in the room facing the direction in which the body was found. He opens the window in that direction and flips a coin towards the floor.
Then he goes to the second floor and repeats the process. He keeps on doing it till the last floor. Then, when he climbs down, he tells the team that it is a murder not suicide.
How did he come to know that it was a murder?
Hint:
At each floor, he did the same task of opening the window and flipping the coin. If it was a suicide, then at least the window at any of the floors must have been left open by the person who jumped off. The situation only suggests that someone pushed him off and then closed the window again. Did you answer this riddle correctly?
YES NO
YES NO
Ida's Microwaved Coffee Riddle
Ida puts her coffee into the microwave, as she does every morning, for exactly two minutes. When the microwave goes off, she opens the door, but then closes the door again and sets the microwave for two more seconds. What good would two more seconds be?
Hint:
To rotate the handle on the mug so she can comfortably remove it. Did you answer this riddle correctly?
YES NO
YES NO
The Cost Of Coffee Riddle
Hint:
Dearth In Ireland Riddle
Hint:
Vampire Savings Riddle
Hint:
Everyone Wants More Riddle
Everyone wants more of it to feel special, and to have more of it opens the door to more opportunity. What is it?
Hint:
The English Channel Riddle
You are in Italy for a holiday. You book a hotel. You go a room. It has only a pair of socks, a light bulb, a TV, a remote, a bag and a phone. You search for the English Channel. How do you find it?
Hint:
Turn the TV on and switch it to a channel originating in England. Did you answer this riddle correctly?
YES NO
YES NO
Boxes Of Balls Riddle
The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.
Boxes are labeled but all labels are wrong!
You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.
How many such operations are necessary to correctly label the boxes?
Boxes are labeled but all labels are wrong!
You are allowed to open one box, pick one ball at random, see its color and put it back into the box, without seeing the color of the other ball.
How many such operations are necessary to correctly label the boxes?
Hint:
Just One!
Because we know all labels are wrong.
So the BW box must be either BB or WW. Selecting one ball from BW will let you know which.
And the other two boxes can then be worked out logically. Did you answer this riddle correctly?
YES NO
Because we know all labels are wrong.
So the BW box must be either BB or WW. Selecting one ball from BW will let you know which.
And the other two boxes can then be worked out logically. Did you answer this riddle correctly?
YES NO
I Can Show You Riddle
I can show you where things are but Im not a tour guide
I have a scale but I dont weigh things
I contain roads but Im not a city
I can be on paper or on a phone but Im not a shopping list
I can show you whats north, south, west and east but Im not a compass
What am I?
I have a scale but I dont weigh things
I contain roads but Im not a city
I can be on paper or on a phone but Im not a shopping list
I can show you whats north, south, west and east but Im not a compass
What am I?
Hint:
Superhero Space Host Riddle
Hint:
A Item Of Danger Riddle
Hint:
Joseph And Lena Riddle
Joseph and Lena are found dead on the floor with some water around. The windows are open and a strong wind draft is blowing the curtains around. How did they die?
Hint:
Joseph and Lena were goldfishes. The wind tipped their bowl over, hence killing them! Did you answer this riddle correctly?
YES NO
YES NO
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