What is always in front of you but can’t be seen?

What does Alexander the Great and Winnie the Pooh have in common?

I am a word of 12 alphabets.

* Alphabets 12, 4, 7, 2, 5 : Eastern beast of burden
* Alphabets 1, 8, 10, 9 are street made famous by Sinclair Lewis.
* Alphabets 11, 3, 6 are past.

On whole it means a person suffering from delusions of greatness.

What Is it ?

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

Until it is measured, not known. Yet how you miss it when it has gone. What is it?

Can you count the number of lines in the below picture?

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.

This was asked in an interview with Coa-Cola.

The interviewer has given me 100 marbles(50 white and 50 black) and two empty boxes.
He then told me that he will leave the room and i need to place all the marbles in two boxes.

And When he come back, he will draw a marble from any of the two box and if the marble is white I will be hired.

Also
* No box can be empty.
* All 100 marbles must be placed in one of the two boxes.

So what should I have done?