The Hijacker Riddle
A man hijacks an airplane transporting both passengers(8 of them) and valuable cargo. After taking the cargo, the man demands nine parachutes, puts one of them on, and jumps, leaving the other eight behind. Why did he want eight?
Hint:
If the officials thought he was jumping with a hostage, they would never risk giving him a faulty parachute. Did you answer this riddle correctly?
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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?
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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?
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Fifty One Bicycles
Hint:
The man was playing a poker game and cheated. The bicycles are a type of card. Did you answer this riddle correctly?
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Add Up To 100 Riddle
With the numbers 123456789, make them add up to 100. They must stay in the same order. You can use addition, subtraction, multiplication, and division. Remember, they have to stay in the same order!
Hint:
Making Glass Riddle
Hint:
World War 1 Riddle
A grandfather is telling his grandson war stories.
At the end of World War 1, I was awarded for my bravery after saving a group of my men, the grandfather says. You see, we were fighting in northern France and one of our enemies threw a grenade at us. I managed to pick it up and throw it away before it exploded. So right after the war ended, a General gave me a sword, engraved with the words Awarded for Bravery and Valor, A True Hero, World War 1.
The grandson thinks about the story for a minute and then says Grandpa, that story can't be true! How did the grandson know?
At the end of World War 1, I was awarded for my bravery after saving a group of my men, the grandfather says. You see, we were fighting in northern France and one of our enemies threw a grenade at us. I managed to pick it up and throw it away before it exploded. So right after the war ended, a General gave me a sword, engraved with the words Awarded for Bravery and Valor, A True Hero, World War 1.
The grandson thinks about the story for a minute and then says Grandpa, that story can't be true! How did the grandson know?
Hint:
It was the only World War at that time and World War 2 had not started yet. Did you answer this riddle correctly?
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Stolen Apple Riddle
Mrs. Stotch is a fifth grade teacher. One of her students took her apple. Mrs. Stotch has narrowed the suspects down to Billy, Paige, and Tyler. Each of the students give these statements:
Billy: I didnt do it.
Paige: I didnt do it.
Tyler: Paige did it!
Mrs. Stotch knows that only one of the kids is telling the truth. Who is telling the truth and who took the apple?
Billy: I didnt do it.
Paige: I didnt do it.
Tyler: Paige did it!
Mrs. Stotch knows that only one of the kids is telling the truth. Who is telling the truth and who took the apple?
Hint:
Billy did it. Paige is telling the truth so she didnt do it. Tyler is lying so he reinforces that Paige didnt do it. Billy is lying so he did it. Did you answer this riddle correctly?
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Japanese Ship Thief Riddle
A Japanese ship was en route in the open sea. The Japanese captain went for a shower removing his diamond ring and Rolex watch on the table. When he returned, his valuables were missing. The captain immediately called the five suspected crew members and asked each one where and what he was doing for the last 15 minutes.
The Filipino cook in a heavy overcoat said, I was in fridge room getting meat for cooking.
The Indian Engineer with a torch in hand said, I was working on generator engine.
The Sri Lankan seaman said, I was on the mast (top of the ship) correcting the flag which was upside down by mistake.
The British radio officer said, I was messaging to company that we are reaching the next port in 72 hours. From now that is Wednesday morning at 10 AM.
The British navigation officer said, I am on night watch, so sleeping in my cabin.
The captain caught the liar. So who is the thief?
The Filipino cook in a heavy overcoat said, I was in fridge room getting meat for cooking.
The Indian Engineer with a torch in hand said, I was working on generator engine.
The Sri Lankan seaman said, I was on the mast (top of the ship) correcting the flag which was upside down by mistake.
The British radio officer said, I was messaging to company that we are reaching the next port in 72 hours. From now that is Wednesday morning at 10 AM.
The British navigation officer said, I am on night watch, so sleeping in my cabin.
The captain caught the liar. So who is the thief?
Hint:
The thief is the Sri Lankan seaman. They are on a Japanese ship, so it will bear a Japanese flag. The Japanese flag will look the same upside down. Did you answer this riddle correctly?
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Four Jolly Men Riddle
Four jolly men sat down to play, And played all night till the break of day. They played for cash and not for fun, With a separate score for every one. When it came time to square accounts, They all had made quite fair amounts. Now, not one has lost and all have gained, Tell me, now, this can you explain?
Hint:
Losing Skin Riddle
Hint:
Three Rivers Riddle
There are three rivers and after each river lies a grave. A man wants to leave the same number of flowers at each grave and be left with none at the end. However, each time he passes through a river, the number of flowers he has doubles. How many flowers does he have to start with so that he is left with none at the end? And how many does he leave at each grave?
Hint:
This problem has an infinite number of solutions modeled by the equation 8a=7n, where a is the amount of flowers the man starts with and n is the number of flowers he leaves at each grave. The simplest and possibly trivial solution would be to start with 0 flowers and leave 0 flowers at each grave. A more significant solution would be to start with 7 flowers and leave 8 at each grave. Any positive integer multiple of this solution also satisfies the conditions. For example, the man starts with 14 flowers and leaves 16 at each grave; so, 14 doubles to 28, and 28-16= 12; 12 doubles to 24, and 24-16= 8; 8 doubles to 16, and 16-16= 0. The result is the same if the man starts with 21 flowers and leaves 24 flowers at each grave, or starts with 28 and leaves 32. Did you answer this riddle correctly?
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The Mountain Of Two Paths
You walk up to a mountain that has two paths. One leads to the other side of the mountain, and the other will get you lost forever. Two twins know the path that leads to the other side. You can ask them only one question. Except! One lies and one tells the truth, and you don't know which is which. So, What do you ask?
Hint:
You ask each twin What would your brother say?. This works because.... Well let's say the correct path is on the left side. So say you asked the liar "What would your brother say?" Well, the liar would know his brother was honest and he would say the left side, but since the liar lies, he would say right. If you asked the honest twin the same question, he would say right, because he knows his brother will lie. Therefore, you would know that the correct path was the left! Did you answer this riddle correctly?
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Tea Cups On The Table
Hint: Try reading the question out loud.
The answer is 3 tea cups because the question was not forty cups it was four tea cups. Did you answer this riddle correctly?
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The Countersign Riddle
Two spies want to get in an enemy's military base. In order to get in they have to give the correct countersign to the guard at the gate after he gives them the sign. So, they wait hidden nearby the gate so that they will overhear the countersign from another soldier.
One soldier comes and the guard gives the sign: "6". The soldier answers "3". The guard lets him pass. Another soldier comes. The guard says "12" and the soldier gives the answer "6". The guard lets him pass. So, the first spy goes at the gate and the guard says "10".The spy, sure that he knew the answer as he was, says "5". Immediately, the guard shoots him dead. Then the other spy, who saw that the other spy was killed when he gave the countersign, had now understood what the right answer would be, whatever the guard's sign was. So, he walks to the gate and the guard says "8".The spy gives the correct answer and the guard lets him in. What was the answer that the spy gave?
One soldier comes and the guard gives the sign: "6". The soldier answers "3". The guard lets him pass. Another soldier comes. The guard says "12" and the soldier gives the answer "6". The guard lets him pass. So, the first spy goes at the gate and the guard says "10".The spy, sure that he knew the answer as he was, says "5". Immediately, the guard shoots him dead. Then the other spy, who saw that the other spy was killed when he gave the countersign, had now understood what the right answer would be, whatever the guard's sign was. So, he walks to the gate and the guard says "8".The spy gives the correct answer and the guard lets him in. What was the answer that the spy gave?
Hint:
5. It's the number of letters it takes to spell the word the guard says. Did you answer this riddle correctly?
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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?
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