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
After The Day Riddle
Hint:
Tomorrow.
The day before yesterday is two days ago.
The day after the day before yesterday (2 days ago) is yesterday.
And two days after yesterday is tomorrow. Did you answer this riddle correctly?
YES NO
The day before yesterday is two days ago.
The day after the day before yesterday (2 days ago) is yesterday.
And two days after yesterday is tomorrow. Did you answer this riddle correctly?
YES NO
One Big Family Riddle
Four people are sitting around a campfire after a long day of recreation, when one man comments: "Do you realize that around this campfire, the four of us include a mother, father, brother, sister, son, daughter, niece, nephew, aunt, uncle and a couple cousins"?. If everyone is related by blood (with no unusual marriages) how is this possible?
Hint:
The campfire circle includes a woman and her brother. The woman's daughter and the man's son are also present. Did you answer this riddle correctly?
YES NO
YES NO
Snow White's Photography Riddle
Hint:
Show White's Dwarfs Riddle
Hint:
A Hot Summers Day Riddle
Hint:
Valentin's Day Pickles Riddle
Hint:
A Small Valentine Riddle
Hint:
Skunks On V-Day Riddle
Hint:
27 Days Riddle
Hint:
The moon. Even though the true moon cycle is about 29.5 days, it takes 27 days, 7 hours, and 43 minutes for our Moon to complete one full orbit around Earth. Thus you can see the full moon every 27 days or you can moon yourself every day in the mirror. Not that youd want to. Does anyone moon themselves? Cant say as Ive ever had the pleasure. Did you answer this riddle correctly?
YES NO
YES NO
Miley And Snow White Riddle
Hint:
Ready For St. Patrick's Day
Hint:
Saint Patrick's Day In April
Hint:
On Saint Patrick's Day you wear green, and on April 15 the government takes away your green. Did you answer this riddle correctly?
YES NO
YES NO
The Smallest Bridge Riddle
Hint:
28 Days Riddle
Hint:
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