Hard riddles

logicprobability

Brothers and sisters

You and a friend are standing in front of two houses. In each house lives a family with two children. "The family on the left has a boy who loves history, but their other child prefers math," your friend tells you. "The family on the right has a 7-year old boy, and they just had a new baby," he explains. "Does either family have a girl?" you ask. "I'm not sure," your friend says. "But pick the family that you think is more likely to have a girl. If they do have a girl, I'll give you $100." Which family should you pick, or does it not matter?
You should pick the house on the left. Specifically, there is a 2/3 chance that the family on the left has a girl, whereas there's only a 1/2 chance that the house on the right has a girl. This is a very counterintuitive riddle. It seems like there should always be a 1/2 chance that a given child is a girl. And in fact there is. The key word there is "given". Because we are not asking about a "given" child for the house on the left. We are asking about what could be either child. Whereas for the house on the right, we are asking about a "given" child...specifically, we're asking about the younger child. There are 3 possibilities for the children in the first house: Younger Older Girl Boy Boy Girl Boy Boy There is no "Girl, Girl" option because we know the house on the left has at least one boy. Since each of these 3 options is equally likely, and 2 of them have one girl, there is a 2/3 chance of there being a girl in the house on the left. For the house on the right, because we already know the older child is a boy, there are only two possibilities: Younger Older Girl Boy Boy Boy And as we can see, there is a 1/2 chance for the house on the right having a girl.
82.72 %
48 votes

cleanmystery

Mystery of the Ancient Temple

Once upon a time there existed a temple in India which housed three identical idols which spoke to the devotees. The idols were of – God of Truth, which always spoke the truth; God of Falsehood, which always lied; and God of Diplomacy which sometimes spoke the truth and at other times lied. The pilgrims come from all parts of the world to get their questions answered by the Gods. But there was a problem. As the idols were indistinguishable, devotees were not sure from which idol to ask their questions and in turn they did not know which God has answered and whether to believe it or not. Once a wise man visited the temple. He asked the question: "Which God is seated at the centre?" to all the three idols. The idol on the left, centre and right replied God of Truth, God of Diplomacy and God of Falsehood respectively. The wise man at once proclaimed that he had solved the mystery of the temple.
The idols from left to right are: God of Diplomacy, God of Falsehood, God of Truth. The God of Truth is not seated on the left because he always speaks the truth whereas the idol on the left replied that the God of Truth is seated at the centre. The God of Truth is also not seated in the centre as he always speaks the truth but the idol at the centre replied that the God of Diplomacy is seated at the centre. Therefore, the God of Truth is seated on the right. As God of Truth is seated on the right, and he always speaks the truth, then the The God of Falsehood is seated at the centre. The God of Diplomacy is seated on the left and he has lied.
79.72 %
90 votes

cleanfunnylogicshort

A millionaire

A kind hearted person Mr. Rawat buy packed food at 3$/packet from United states and sells them at 1$/packet at Africa. After some time he becomes a millionaire. How come the guy become millionaire?
He started out as a billionaire, but lost so much money in his good works (by giving to poor people) that he became a millionaire.
79.19 %
58 votes

logicmysteryscary

Shot to death while in his car

A man was shot to death while in his car. There were no powder marks on his clothing which indicated that the gunman was outside the car. However, all the windows were up and the doors locked. After a close inspection was made, the only bullet holes discovered were on the man's body. How was he murdered?
The victim was in a convertible.
77.03 %
130 votes

logicmystery

Two Hourglasses

You have two sand hourglasses, one that measures exactly 4 minutes and one that measures exactly 7 minutes. You need to measure out exactly 2 minutes to boil an egg. Using only these two hourglasses, how can you measure out exactly 2 minutes to boil your egg?
Flip over both hourglasses at the same time. After 4 minutes, the 4-minute hourglass will be done, and there will be 3 minutes left in the 7-minute hourglass. Immediately flip the 4-minute hourglass over again. After 3 more minutes, the 7-minute hourglass will be done, and there will be exactly 1 minute left in the 4-minute hourglass. Immediately flip the 7-minute hourglass over again. After 1 more minute, the 4-minute hourglass will be done again, and there will be exactly 6 minutes left in the 7-minute hourglass. Immediately flip over the 4-minute hourglass. After 4 more minutes, the 4-minute hourglass will be done again, and there will be exactly 2 minutes left in the 7-minute hourglass. At this point, put your egg in the boiling water. When the 7-minute hourglass is done, it will have been exactly 2 more minutes, and your egg will have boiled just right.
77.02 %
63 votes

logicmystery

Kidnapped kid

A rich man's son was kidnapped. The ransom note told him to bring a valuable diamond to a phone booth in the middle of a public park. Plainclothes police officers surrounded the park, intending to follow the criminal or his messenger. The rich man arrived at the phone booth and followed instructions but the police were powerless to prevent the diamond from leaving the park and reaching the crafty villain. What did he do?
This is a true story from Taiwan. When the rich man reached the phone booth he found a carrier pigeon in a cage. It had a message attached telling the man to put the diamond in a small bag which was around the pigeon's neck and to release the bird. When the man did this the police were powerless to follow the bird as it returned across the city to its owner.
76.59 %
67 votes

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