Crossing The Bridge Riddle
There are two villages separated with a river. Each day, four people cross the river through a bridge to work on the other side and earn for their families. On one night when they were returning from work, they noticed that the bridge was about to collapse. Now all of them wanted to cross the bridge before it collapsed as no one wanted to be stuck on that end without their families.
They had just one torch with them and since it was the night time, they could not see without it. The bridge had become weak and it could only accommodate two people at a time. It was going to collapse in just 17 minutes.
The four people took different times to cross the bridge. First one took only a minute, second one took 2 minutes, third one took 5 minutes and the last one took 10 minutes.
How would all of them have managed to cross the bridge in time?
They had just one torch with them and since it was the night time, they could not see without it. The bridge had become weak and it could only accommodate two people at a time. It was going to collapse in just 17 minutes.
The four people took different times to cross the bridge. First one took only a minute, second one took 2 minutes, third one took 5 minutes and the last one took 10 minutes.
How would all of them have managed to cross the bridge in time?
Hint:
Let us denote the four people with A, B, C and D.
A takes 1 minute to cross, B takes 2, C takes 5 and D takes 10.
A and B cross first spending 2 minutes.
A comes back with torch taking 1 minute.
C and D cross taking 10 minutes.
B comes back with torch taking 2 minutes.
Finally, A and B cross the bridge taking 2 minutes.
2 + 1 + 10 + 2 + 2 = 17 minutes
Thus, this is the way they all managed to cross that bridge that night. Did you answer this riddle correctly?
YES NO
A takes 1 minute to cross, B takes 2, C takes 5 and D takes 10.
A and B cross first spending 2 minutes.
A comes back with torch taking 1 minute.
C and D cross taking 10 minutes.
B comes back with torch taking 2 minutes.
Finally, A and B cross the bridge taking 2 minutes.
2 + 1 + 10 + 2 + 2 = 17 minutes
Thus, this is the way they all managed to cross that bridge that night. Did you answer this riddle correctly?
YES NO
A Boy At The Carnival
A young boy was at the carnival. He was walking past a kiosk where an old man was sitting.
"Do you want to play a game?" the old man said to him.The young boy was intrigued. "What kind of game?" he asked.
"It's a very simple game." said the old man. "I will tell you the rules. I have ten large metal boxes. Inside one of the boxes is the prize money. One thousand dollars."
"A thousand bucks, huh?" asked the boy. "What's the catch?"
"The boxes are sturdy and strong," said the old man. "Much too strong to be opened with your bare hands. They are also airtight and cannot be damaged by a hammer, an axe or even a chainsaw."
"So they're impossible to open?" said the boy.
"Not impossible." said the man. "I have a blowtorch which can be used to open the boxes."
"Is there a time limit?" asked the boy.
"You can take as much time as you want." said the old man. "When you find the prize money, it's all yours. So, do you want to play the game?"
"Well, I don't how I could possibly lose," said the boy. "OK. I'll play your game."
The old man smiled. "I'll make it very easy for you", he said. "There are ten metal boxes, but if you give me five dollars, I will start you right next to the prize money."
The boy happily took out his wallet and handed a crisp five dollar note to the old man. There was a mischievous grin on the old man's face.The game started.The prize money was right in front of the boy. He could see it. He could touch it.Even though he won the game, the boy was never able to spend the money. He died shortly after he won the game.
How did the boy die?
"Do you want to play a game?" the old man said to him.The young boy was intrigued. "What kind of game?" he asked.
"It's a very simple game." said the old man. "I will tell you the rules. I have ten large metal boxes. Inside one of the boxes is the prize money. One thousand dollars."
"A thousand bucks, huh?" asked the boy. "What's the catch?"
"The boxes are sturdy and strong," said the old man. "Much too strong to be opened with your bare hands. They are also airtight and cannot be damaged by a hammer, an axe or even a chainsaw."
"So they're impossible to open?" said the boy.
"Not impossible." said the man. "I have a blowtorch which can be used to open the boxes."
"Is there a time limit?" asked the boy.
"You can take as much time as you want." said the old man. "When you find the prize money, it's all yours. So, do you want to play the game?"
"Well, I don't how I could possibly lose," said the boy. "OK. I'll play your game."
The old man smiled. "I'll make it very easy for you", he said. "There are ten metal boxes, but if you give me five dollars, I will start you right next to the prize money."
The boy happily took out his wallet and handed a crisp five dollar note to the old man. There was a mischievous grin on the old man's face.The game started.The prize money was right in front of the boy. He could see it. He could touch it.Even though he won the game, the boy was never able to spend the money. He died shortly after he won the game.
How did the boy die?
Hint:
The man put the inside of the box since he said for five dollars, he'd put the boy next to the money. Since the box was airtight, he suffocated Did you answer this riddle correctly?
YES NO
YES NO
Two Fathers Two Sons Riddle
Hint:
Losing A New York Bet
You are hanging around in NYC when a person approaches you.
"Leaving the bald people aside, I can bet a hundred bucks that there are two people living in NYC who have same number of hairs on their heads," he says to you.
You say that you will take the bet. After talking to the man for a couple of minutes, you realize that you have lost the bet.
What did the person say to you that proved his statement ?
"Leaving the bald people aside, I can bet a hundred bucks that there are two people living in NYC who have same number of hairs on their heads," he says to you.
You say that you will take the bet. After talking to the man for a couple of minutes, you realize that you have lost the bet.
What did the person say to you that proved his statement ?
Hint:
This problem can be best solved using the pigeonhole principle.
The argument will go like this:
Assume that all the non-bald people in NYC have different number of hairs on their head. The population is about 9 million and let us assume that there are 8 million among them who are not bald.
Now, those 8 million people need to have different number of hairs. On an average, people have just 100, 000 hairs on their head. If we keep on assuming that there is someone with just one hair, someone with two, someone with three and so on, there will be 7, 900, 00 other people left who will have more than 100, 000 hairs on their head and need different number of hairs.
Now, as per this assumption, if we keep increasing one hair for each person, to make everybody hair different in numbers, we will come across someone with 8, 000, 000 hairs. But that is practically impossible (even 1, 000, 000 is impossible). Thus there must be two people who are having same number of hairs. Did you answer this riddle correctly?
YES NO
The argument will go like this:
Assume that all the non-bald people in NYC have different number of hairs on their head. The population is about 9 million and let us assume that there are 8 million among them who are not bald.
Now, those 8 million people need to have different number of hairs. On an average, people have just 100, 000 hairs on their head. If we keep on assuming that there is someone with just one hair, someone with two, someone with three and so on, there will be 7, 900, 00 other people left who will have more than 100, 000 hairs on their head and need different number of hairs.
Now, as per this assumption, if we keep increasing one hair for each person, to make everybody hair different in numbers, we will come across someone with 8, 000, 000 hairs. But that is practically impossible (even 1, 000, 000 is impossible). Thus there must be two people who are having same number of hairs. Did you answer this riddle correctly?
YES NO
10 Boxes Riddle
There are ten boxes containing some balls. Each of the ball weighs exactly 10 grams. One of those boxes have defective balls (all the defective balls weigh 9 grams each).
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
An electronic weighing machine is provided to you and you are allowed only one chance of weighing on it.
How will you find out which box has defective balls ?
Hint:
Let us simplify boxes by naming them from 1 to 10.
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
Now the trick here is to pick different number of balls from different boxes. So to simplify things, we will pick balls corresponding to box number.
Thus, pick 1 ball from Box 1, 2 balls from box 2, 3 balls from box 3 and so on. You will have 55 balls altogether. Now, put them all in the balance.
If all balls were weighing accurate 10 grams, the total weight of the 55 balls would have been 550 grams. But one of the box must have had the defective balls.
Suppose if the defective balls were in box number 2, then the total weight will be 2 grams less than 550. If the defective balls were in box 8, the total weight will be less than 8 grams from 550. In this way, you will be able to identify which box has the defective balls. Did you answer this riddle correctly?
YES NO
2 Burning Candles
Hint:
Burn one candle from both the ends and simultaneously burn the other candle from just one end. In half an hour, the first candle would have been burnt fully and the second one would have been burnt half. Now light the other end of the second candle as well. In this way, the second candle will take only half the time (30/2 = 15) to burn fully.
Thus, you will have measured forty five minutes. Did you answer this riddle correctly?
YES NO
Thus, you will have measured forty five minutes. Did you answer this riddle correctly?
YES NO
The Same Mother Riddle
There are two girls
They were born on the same day, same month, and same year.
They were born from the same mother and came from the same womb, yet they are not twins? How can this be?
They were born on the same day, same month, and same year.
They were born from the same mother and came from the same womb, yet they are not twins? How can this be?
Hint:
Invitro fertilization. Two different eggs fertilized at different times and implanted into the mother's womb. Did you answer this riddle correctly?
YES NO
YES NO
Two Girls Born The Same Day 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?
YES NO
YES NO
Two Gates Riddle
You have one question to ask one of the angels, in order to find out which gate will lead you to Heaven. What would that question be?
Hint:
The question is: What would the other angel say, if I asked which gate leads to Heaven?. And do exactly the opposite of what the angel says.
If the left gate leads to Heaven:
The angel that tells the truth will say that it's the right gate since it knows that the other angel will lie.
The angel that lies will also say that it's the right gate since it knows that the other angel will tell the truth.
The same explanation applies if the right gate leads to Heaven. Did you answer this riddle correctly?
YES NO
If the left gate leads to Heaven:
The angel that tells the truth will say that it's the right gate since it knows that the other angel will lie.
The angel that lies will also say that it's the right gate since it knows that the other angel will tell the truth.
The same explanation applies if the right gate leads to Heaven. Did you answer this riddle correctly?
YES NO
Two Doors Riddle
You are imprisoned in a chamber with two doors as the only exit. One door leads to death by cancer, filled with complications and malpractice; the other door leads to riches of jewelry, money and fine clothing for the rest of your life. There are two guards standing before you: one guard always lies; the other always tells the truth. Of course, you dont know their identities. You can ask only one question to save your life. What should you ask?
Hint:
This is a logic question and can be answered if one realizes that the TRUTH of a LIE is a LIE, and the LIE of a TRUTH is a LIE. You need one guard to give you the other guards answer. Knowing this one could ask a question like, If I were to ask the other guard which door leads to freedom, what would he say?
If you ask the guard who always tells the truth, he would tell you the other guard would point you to the door of death. If you ask the guard who always lies, he would tell you the opposite door of the truth-telling guard and point you to the door of death. In either case, both guards will point to the door of death so you should choose the other one. Did you answer this riddle correctly?
YES NO
If you ask the guard who always tells the truth, he would tell you the other guard would point you to the door of death. If you ask the guard who always lies, he would tell you the opposite door of the truth-telling guard and point you to the door of death. In either case, both guards will point to the door of death so you should choose the other one. Did you answer this riddle correctly?
YES NO
Taking Cups Away
Hint:
One, as that is the only one you took away and that is all that you have. The rest still remain where there were. Did you answer this riddle correctly?
YES NO
YES NO
2 Monkeys Riddle
Hint:
Two Planes
There are two planes. One is going from New York to London at a speed of 600 MPH. The other is traveling from London to New York at a speed of 500 MPH.
When the planes meet which one will be closer to London?
When the planes meet which one will be closer to London?
Hint:
Three Men On A Boat
Hint: They have to use the boat.
They throw one cigarette overboard and made the boat a cigarette lighter. Did you answer this riddle correctly?
YES NO
YES NO
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