What does below chemistry rebus means?

Make the seating arrangement of 10 children in such a way that there are 5 rows with 4 children in each row.

A man who was outside in the rain without an umbrella or hat didn’t get a single hair on his head wet. Why?

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 does this rebus means ?

PROG WORKRESS

A man is approaching a broad and barren land. He has a package with him. If somehow, he is unable to open the package before reaching the land, he will die.

Can you guess what is present in the package?

I am a white box having no key or lid.
Yet there is a golden treasure inside it.

What Am I?

Solve the mathematical equation in the picture below.

Can you find the thief by just looking at the picture below?

John enters a small room. The Door Closes.
When the door opens, John is in a larger room.

Explain?