What is harder to catch the faster you run?

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?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

Take away the whole and some still remain. What is it?

Can you Find and name the hidden bird in the picture below ?

What has 13 hearts but no other organs?

What Does this text mean:

important=important

I have a five and a three-gallon jar. Assuming there is an infinite supply of water, how can I measure one-gallon water?

What English word has three consecutive double letters?

A girl was sitting in her hotel room when she heard a knock on the door. She opened the door and found that a man was standing outside.
The man said, "Oh! I am really sorry, I thought this was my room."
He then walked through the corridor to the elevator. The girl did not know the man. She closed her door and called security asking them to apprehend the man.
What made her suspicious of that man? He might have been genuinely mistaken.