If you say my name, I will no longer exist. What am I?

You are presented with three boxes. One of them has a red ball inside and the other two have a black ball inside each of them. You are asked to pick up the one with red ball and you pick one. Now, one of the other boxes is opened and it is found to have a black ball.

You are presented with a chance to change your box with the one that is left closed. Will you change your box? Why or why not?

Can you identify if it's a murder or a suicide ?

There is a family that live in a round house. The two parents go out for a movie and leave a babysitter to watch their son. They come back and the kid was not there. Some one kidnapped him. The maid said she was cleaning in a corner. The cook said he was making pizza. The babysitter said she was getting a board game. Who kidnapped him.

John was running from 40 thieves. John has got 3 gold boxes which weigh as 4kg, 2kg, and 1kg respectively. A witty man asked John to stay with him for seven days in exchange for 1kg gold per day. John needs to stay there for seven days and also do not want to give the witty man any advance. How can John pay for his seven days stay?

You along with your friend are standing in front of two houses. Each of those houses inhabits a family with two children.

Your friend tells you the below two facts:
1) On your left is a family that has a boy who likes accounts but the other child loves science.
2) On the right is a family with a seven-year-old boy and a newborn baby.

You ask him, "Does either of the family have a girl?"

To this, he replies, "I am not quite sure. But can you guess that? If you are right, I will give you $500."

Which family do you think is likely to have a girl?

If,
29 - 1 = 30
9 - 1 = 10
14 - 1 = 15

Based on similar logic, Can you prove that the below algebraic equation is true?
11 - 1 = 10 ?

Three cars are driving on a track that forms a perfect circle and is wide enough that multiple cars can pass anytime. The car that is leading in the race right now is driving at 55 MPH and the car that is trailing at the last is going at 45 MPH. The car that is in the middle is somewhere between these two speeds.
Right now, you can assume that there is a distance of x miles between the leading car and the middle car and x miles between the middle car and the last car and also, x is not equal to 0 or 1.
The cars maintain their speed till the leading car catches up with the last car and then every car stops. In this scenario, do you think of any point when the distance between any two pairs will again be x miles i.e. the pairs will be x distance apart at the same time ?

Once upon a time, there was a bus conductor who was extremely rude to all the passengers. On a certain day, a young and charming lady tried boarding the bus. But he did not stop the bus. As a result, the girl came under the bus and was killed. The agitated passengers took the conductor to the police station. The police took him to the court for trial. In the court, the judge gave him death sentence.

He is then taken to the electrocution chamber. In that room, there is a chair in the center of the room and a banana peel lies just behind the chair. The conductor is strapped to that chair and is being exposed to a high voltage current. But to everyone�s surprise, he is able to survive through the current that is enough to kill two people at once. The judge decides that it is a miracle and sets the conductor free.

The conductor then returns back to his profession. After a few months, a middle aged lady tries to board the bus. The conductor does not stop the bus and as a result the lady gets run over by the bus which kills her on the spot. The agitated passengers take him to the police. The police takes him to the court for the trial. In the court, the judge decides for capital punishment for the conductor.

The conductor is taken to the electrocution chamber again. In that chamber, there is a chair in the middle of the room and a banana peel lies behind the chair. He is strapped to the chair and exposed to a high voltage. To everyone�s surprise, he survives again. Thus, the judge sets him free.

The conductor returns back to his profession. After a few months. An old lady tries to board the bus. The bus conductor after remembering his previous actions, stops the bus. But unfortunately, the old lady slips while climbing up the bus and dies due to his injuries. The passengers take him to the police again. The police takes him back to the court. Though the judge knows that he is not guilty, he sentences him to death knowing his previous record.

The conductor is taken to the electrocution chamber again. He is strapped to the chair in the center of the room behind which, there is a banana peel. He is exposed to the current and this time he is killed instantly.

Why did he die this time and not the previous times?

The host of a game show offers the guest a choice of three doors. Behind one is an expensive car, but behind the other two are goats.
After you have chosen one door, he reveals one of the other two doors behind which is a goat (he wouldn't reveal a car).

Now he gives you the chance to switch to the other unrevealed door or stay at your initial choice. You will then get what is behind that door.

You cannot hear the goats from behind the doors, or in any way know which door has the prize.

Should you stay, or switch, or doesn't it matter?