Can you replace the question mark with the correct number?

Can you decipher the below rebus?

PBLUESAISNUERSES

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?

Christina is older than Kareena and Karishma. Katrina is older than Karishma and younger than Kareena. If Kareena has a brother named John, who is older than Christina, who's the youngest?

I speak without a mouth, and hear without ears. I have no-body, but I come alive with the wind. What am I?

If 24H in a D => 24 hours in a day.
What does "64S on CB" stand for?

How can I get the answer 24 by only using the numbers 8,8,3,3?

You can use the main signs add, subtract multiply and divide.

What does this rebus puzzle means ?

You can take four of the five letters out of this word, but the pronunciation never changes. What is the word?

I am a type of vehicle that has two wheels and is powered by humans. What am I?
Hint 1: You can ride me for exercise.
Hint 2: I am environment-friendly.