What building has the most stories?

You have a three-gallon and a five-gallon measuring device. You wish to measure out four gallons.

It is always ahead of me yet I can never see it. What is it?

I have cities, but no houses. I have mountains, but no trees. I have water, but no fish. What am I?

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?

What word does this rebus represent?

meta meta
meta meta

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

I was born in a small house and I live in it all alone. No windows and no doors have been assigned to my house. The only way I can go out is by breaking through the walls of my house.

Who am I?

Two guards were on duty outside a barracks. One faced up the road to watch for anyone approaching from the North. The other looked down the road to see if anyone approached from the South. Suddenly one of them said to the other, "Why are you smiling?"

How did he know his companion was smiling?

How many times can you subtract the number 5 from 25?