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
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Because when he tried to make a second one he made a Boo-Boo Did you answer this riddle correctly?
YES NO
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Strawberry Jam Stain Riddle
The Smith family is a very wealthy family that lives in a big, circular home. One morning, Mr. Smith woke up and saw a strawberry jam stain on his new carpet. He figured out that everyone who was there that morning had a jam sandwich. From the following statements, figure out who spilled the jam.
Billy Smith: I was outside playing basketball.
The Maid: I was dusting the corners of the house.
Chef: I was starting to make lunch for later.
Who is lying?
Billy Smith: I was outside playing basketball.
The Maid: I was dusting the corners of the house.
Chef: I was starting to make lunch for later.
Who is lying?
Hint:
The maid was lying. There are no corners in a circular house.
Did you answer this riddle correctly?
YES NO
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YES NO
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One contains something black
And the other something white
Add these to what you eat
To make sure that they taste right.
What are we?
And the other something white
Add these to what you eat
To make sure that they taste right.
What are we?
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He waves his hands and says "Poof! you're now a bowl of cereal!" Did you answer this riddle correctly?
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