What do you answer even though it never asks you questions?

Can you replace the question mark with the correct letter?

6 + 6 + 6 = N
7 + 7 + 7 = E
8 + 8 + 8 = R
0 + 0 + 0 = ?

Why do you find that most of the buildings are deprived of the 13th floor?

What kind of band never plays music?

Analyze and find the missing item in the sequence:
16, 06, 68, 88, __, 98

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

Which statement is true out of the following?
One statement here is false.
Two statements here are false.
Three statements here are false.

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?

One day, John and his friends were playing around. Jacob hit something with a Pin and it popped. John's dad came into the room that very moment, but he wasn't mad. In fact, he was smiling. What did Jacob hit?

You may enter, but you may not come in. I have space, but no room. I have keys, but open no lock. What am I?