Why are all black people so quick ?

Count the number of triangles in the given picture.

What number divided by 4 is the same as that number minus 4?

When I get multiplied by any number, the sum of the figures in the product is always me. 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 brings you down but never up?

What does it mean?

What am I?

Can you decipher the below rebus?

PBLUESAISNUERSES

If you had a pizza with crust thickness 'a' and radius 'z', what's the volume of the pizza?