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?

You see a boat filled with people, yet there isn’t a single person on board. How is that possible?

A crime was committed at baker street. Ibrahim Dakota who was shot in the stomach was the main suspect. Sherlock questioned the suspect. The conversation started as:
Sherlock: What's your story, Ibrahim?
Ibrahim: I was walking around baker street and suddenly a man from the back shot me. I ran as fast as I could to save my life".
Sherlock: That is enough (and ask the police to arrest him).

Why does Sherlock think he is the murderer?

Our product and our sum always give the same answer. Who are we?

The square root of number 121 is "11". What is the square root of the number "12345678987654321."?

Railroad Crossing, look out for the cars. Can you spell that, without any R's ?

If six children and two dogs were under an umbrella, how come none of them got wet?

Can you make the number 24 by utilizing the numbers 1, 3, 4 and 6? You must use one number only one time and you can use mathematical operation symbols anytime anywhere.

Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

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