3 Envelops Riddle
You are sitting in front of your interviewer. He gives you three envelopes. One of them contains an offer letter and the other two are empty. You pick up one of them. Now, the interviewer opens up one of the envelope lying on the table and you find out that it is blank.
Now, he gives you a chance to switch your envelope with the one on the table. Would you switch it? Why or why not?
Now, he gives you a chance to switch your envelope with the one on the table. Would you switch it? Why or why not?
Hint:
Yes, you should switch the envelope. In the beginning when you picked up the envelope, you had a 1/3 probability of finding an offer letter in the envelope. There was 2/3 chance that the letter was there in the two envelopes on the table.
If you keep your selected envelope, you still have a 1/3 chance of finding an offer letter in that. However, since the interviewer has removed one empty envelope from the table, if you switch, you have a probability of 2/3 that the offer letter is inside that. Did you answer this riddle correctly?
YES NO
If you keep your selected envelope, you still have a 1/3 chance of finding an offer letter in that. However, since the interviewer has removed one empty envelope from the table, if you switch, you have a probability of 2/3 that the offer letter is inside that. Did you answer this riddle correctly?
YES NO
Attacked By A Burglar Riddle
My wife was attacked by a burglar when I was on my way home from work. She stabbed him with a butcher knife and killed him. The police say it was an obvious case of self-defense. When I went to pick her up from the police station, she said. - "When I heard the doorbell I thought it was you, but then a masked man jumped me as soon as I opened the door!" - "You must have been so scared" - I said - "But you're safe now" - I hugged her tightly.
How did she kill the burglar so fast when he attacked her at the door?
How did she kill the burglar so fast when he attacked her at the door?
Hint:
His wife came to the door with a butcher knife because she thought her husband was coming home. She was planning to kill the husband. Did you answer this riddle correctly?
YES NO
YES NO
Two Keys Riddle
Hint:
Going To Heaven Riddle
Stephen died of heart attack. His soul was received in heaven. He was astonished to find himself as young as he had been in his young adult age. He looked around and there were thousands of young and naked people. His eyes searched to find someone familiar and suddenly he noticed Adam and Eve.
How did Stephen recognize them?
How did Stephen recognize them?
Hint:
Adam and Eve were the only people without navel. As they were not born out of a mother, they never had umbilical cords and thus never had navels. Did you answer this riddle correctly?
YES NO
YES NO
The Piggy Bank Riddle
A girl liked to collect money in a piggy bank. She bought pink colored piggy bank when she was 10 years old. She put $250 in the box on each of her birthday. Her younger sister took $50 out of her piggy bank on her birthday. The girl died when she was 50 years old due to an incurable disease.
When the piggy bank was opened, it had just $500. How can that be possible?
When the piggy bank was opened, it had just $500. How can that be possible?
Hint:
The girl was born on 29 February. Thus her birthday came once in four years only while her sister was born on a normal day and celebrated her birthday every year. Thus the girl had a chance of depositing money only 10 times in 4 years through which she collected $2500 while her sister took $50 from the piggy bank every year making the total amount to be $2000. Thus when the piggy bank was opened, it had just $500. Did you answer this riddle correctly?
YES NO
YES NO
The Card Trick Riddle
A couple had to take shelter in a hotel for they could not proceed their journey in the rain. Having nothing to do at all, they started playing cards. Suddenly there was a short circuit and the lights went off. The husband inverted the position of 15 cards in the deck (52 cards normal deck) and shuffled the deck.
Now he asked his wife to divide the deck into two different piles which may not be equal but both of them should have equal number of cards facing up. There was no source of light in the room and the wife was unable to see the cards.
For a certain amount of time, she thought and then divided the cards in two piles. To the husbands astonishment, both of the piles had equal number of cards facing up.
How did she do it?
Now he asked his wife to divide the deck into two different piles which may not be equal but both of them should have equal number of cards facing up. There was no source of light in the room and the wife was unable to see the cards.
For a certain amount of time, she thought and then divided the cards in two piles. To the husbands astonishment, both of the piles had equal number of cards facing up.
How did she do it?
Hint:
The answer is very simple. All she had to do is take the fifteen cards from the top and reverse them. This would make another pile out of that and there will be two piles - one of 15 cards and one of 37 cards. Also both of them will have the same number of inverted cards.
Just think about it and if the mathematical explanation will help you understand better, here it is.
Assume that there were p inverted cards initially in the top 15 cards. Then the remaining 37 cards will hold 15-p inverted cards.
Now when she reverses the 15 cards on the top, the number of inverted cards will become 15-p and thus the number of inverted cards in both of the piles will become same. Did you answer this riddle correctly?
YES NO
Just think about it and if the mathematical explanation will help you understand better, here it is.
Assume that there were p inverted cards initially in the top 15 cards. Then the remaining 37 cards will hold 15-p inverted cards.
Now when she reverses the 15 cards on the top, the number of inverted cards will become 15-p and thus the number of inverted cards in both of the piles will become same. Did you answer this riddle correctly?
YES NO
The Perfect Pill Riddle
The world is facing a serious viral infection. The government of various countries have issued every citizen two bottles. You as well have been given the same. Now one pill from each bottle is to be taken every day for a month to become immune to the virus. The problem is that if you take just one, or if you take two from the same bottle, you will die a painful death.
While using it, you hurriedly open the bottles and pour the tablets in your hand. Three tablets come down in your hand and you realize they look exactly the same and have same characteristics. You cant throw away the pill as they are limited and you cant put them back or you may put it wrong and may die someday.
How will you ensure that you are taking the right pill?
While using it, you hurriedly open the bottles and pour the tablets in your hand. Three tablets come down in your hand and you realize they look exactly the same and have same characteristics. You cant throw away the pill as they are limited and you cant put them back or you may put it wrong and may die someday.
How will you ensure that you are taking the right pill?
Hint:
You must put labels on the tablets as A and B before using. In that case, if you pour tablets together, you will get 3A, 2A 1B, 1A 2B or 3B. If they are from the same bottles you can take one from another bottle and save the remaining two for another day. If you get two from same and one from other, you can draw one from another bottle and you will have two pairs of which you can eat one and save the other. Did you answer this riddle correctly?
YES NO
YES NO
The Multistory Building Suicide Riddle
A homicide detective is called upon a crime scene. He finds that a body is lying on the ground in front of a multistory building. By all the means, it looks like a simple suicide case. But there are doubts in his mind.
He goes to the first floor and moves into the room facing the direction of the body. He opens the window in that direction and looks down towards his team. The he goes to the second floor and again moves into the room facing that direction, opens the window and looks down at his team.
He continues with the same process till the top floor. After that, he returns back to where his team is standing. He tells them that it is a suicide.
How did he come to such a conclusion?
He goes to the first floor and moves into the room facing the direction of the body. He opens the window in that direction and looks down towards his team. The he goes to the second floor and again moves into the room facing that direction, opens the window and looks down at his team.
He continues with the same process till the top floor. After that, he returns back to where his team is standing. He tells them that it is a suicide.
How did he come to such a conclusion?
Hint:
At every floor, the detective had to open the window himself. If the man had committed suicide, then at least one of the windows must have been open. A person who is committing suicide wont close the window behind him. Thus he knows that someone pushed him off the edge and closed the window afterwards. Did you answer this riddle correctly?
YES NO
YES NO
The River Crossing
A river should be crossed by a father, a mother and their two sons and two daughters.
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.
How will they cross the river?
There are some rules that should be followed while crossing the river. There can be only two people in the raft while crossing. The daughters cannot be with their father unless there is the presence of the mother. The sons cannot be with their mothers unless the father is present. Unless the guard is on the board, the criminals cannot be with any of the family members. Only the adults like the father, the guard, and the mother knows to use the raft.
How will they cross the river?
Hint:
The guard and the prisoner cross the river
The guard comes back
The guard and the girl cross the river.
The guard and the prisoner comes back.
The mother and the girl cross the river.
Mother comes back
The mother and the father cross the river
Father comes back
The guard and the prisoner cross the river
Mother comes back
The father and the mother cross the river
Father comes back
The father and the boy cross the river
The guard and the prisoner comes back
The guard and the boy cross the river
The guard comes back
The guard and the prisoner cross the river. Did you answer this riddle correctly?
YES NO
The guard comes back
The guard and the girl cross the river.
The guard and the prisoner comes back.
The mother and the girl cross the river.
Mother comes back
The mother and the father cross the river
Father comes back
The guard and the prisoner cross the river
Mother comes back
The father and the mother cross the river
Father comes back
The father and the boy cross the river
The guard and the prisoner comes back
The guard and the boy cross the river
The guard comes back
The guard and the prisoner cross the river. Did you answer this riddle correctly?
YES NO
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
150 Pens Riddle
Rihanna brought home 150 pens but while packing them, she misplaced some of them. When her brother asked how many she had misplaced, she told him:
If you count in pairs, one will remain
If you count in a group of three, two will remain
If you count in a group of four, three will remain
If you count in a group of five, four will remain
If you count in a group of six, five will remain
If you count in a group of seven, nothing will remain.
How many pens do you think has she misplaced ?
If you count in pairs, one will remain
If you count in a group of three, two will remain
If you count in a group of four, three will remain
If you count in a group of five, four will remain
If you count in a group of six, five will remain
If you count in a group of seven, nothing will remain.
How many pens do you think has she misplaced ?
Hint:
Peter's Proposal Riddle
A couple - Peter Parker and Mary Jane are madly in love with each other, but they live miles apart. Peter wants to send a gold ring to Mary to celebrate their first anniversary together but in a country where people steal anything unlocked, he can't send it to her without locking it inside a box.
Now, Peter and Mary have a lot of padlocks with them, but they don't have the key to the padlock for one another's.
How will Peter send the ring now?
Now, Peter and Mary have a lot of padlocks with them, but they don't have the key to the padlock for one another's.
How will Peter send the ring now?
Hint:
Peter will have to use a lock box that can hold two locks. He will put the ring in a box and will mail it to Mary. Upon receiving the box, Mary will put her own lock box inside and will send back to Peter. Peter can then-then take off his lock and send it off to Mary again. Did you answer this riddle correctly?
YES NO
YES NO
The Useless Keys Riddle
Hint:
Finding The Car Riddle
There are three doors in front of you. New car waits behind one of them; goat is hidden behind each of the remaining two. You may open one of the doors and get what is behind them. You want the car off course. You choose your door. Moderator (who knows where the car is) than opens one of the remaining doors and shows that there is goat. Now he gives you the opportunity to change your decision.
You are standing in front of two closed doors. Will you change your decision?
You are standing in front of two closed doors. Will you change your decision?
Hint: It matters whether you change your decision or not.
Imagine there were one hundred doors and moderator would open all but two.
Its better to change the door.
You win in case you chose wrong door at first (odds 2-in-3).
If you dont change the door you win only in case you originally picked the correct door (1-in-3).
Did you answer this riddle correctly?
YES NO
You win in case you chose wrong door at first (odds 2-in-3).
If you dont change the door you win only in case you originally picked the correct door (1-in-3).
Did you answer this riddle correctly?
YES NO
Haunted Halloween House Riddle
To spice up your Halloween, you decide to enter a haunted house with your girlfriend. As you enter, an eerie silence embraces you and you can see nothing because its dark. You fumble your way and try your luck to find the switches, but it turns out to be a waste as there is no electricity connection to the house.
When you decide to turn back, the door closes on you and you are trapped in the house with your girlfriend who has now started panicking.
While you are trying to console her, an evil laughter takes you by surprise. Then, you see a faint figure who tells you that you have three doors in front of you and you must take one of them; it is the only way to free yourself. The figure describes that the first door opens up to a compact space filled with a swarm of deadly bees and you will be stung endlessly by them. The second door opens up to the electricity chairs. You both will be strapped to the chairs for five minutes and exposed to high voltage electricity. The third door opens up with a pit that has no bottom and you will keep falling endlessly into nothingness.
While this leaves you all panicked, which door will you choose if you have no other choice?
When you decide to turn back, the door closes on you and you are trapped in the house with your girlfriend who has now started panicking.
While you are trying to console her, an evil laughter takes you by surprise. Then, you see a faint figure who tells you that you have three doors in front of you and you must take one of them; it is the only way to free yourself. The figure describes that the first door opens up to a compact space filled with a swarm of deadly bees and you will be stung endlessly by them. The second door opens up to the electricity chairs. You both will be strapped to the chairs for five minutes and exposed to high voltage electricity. The third door opens up with a pit that has no bottom and you will keep falling endlessly into nothingness.
While this leaves you all panicked, which door will you choose if you have no other choice?
Hint:
You must choose the door that opens with electric chairs. This is because there is no electricity in the house. Thus, you will just have to sit on the chairs for five minutes and then you will be free to go. Did you answer this riddle correctly?
YES NO
YES NO
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