If you’ve got me, you want to share me; if you share me, you haven’t kept me. What am I?

What do you see in the given picture?

A mile-long train is moving at sixty miles an hour when it reaches a mile-long tunnel. How long does it take the entire train to pass through the tunnel?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?

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?

What's the only room from which no one can enter or leave

A plane crashed between the border of Mexico and America. Where do you bury the survivors?

What work can one never finish?

How high do you have to count before you use the letter “a” in the English spelling of the whole number?

A man is found dead with a knife in his back When the investigation is done. A chair lays beside him and the forensic team finds moisture around the body.

If he committed suicide, how did he do it?