Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

I make a loud sound when I’m changing. When I do change, I get bigger but weigh less. What am I?

When it's bad luck to meet a black cat?

One night, Louis and Adam were sitting together. Adam was watching a movie while his wife Louis was reading a mystery book. Suddenly the power went out and Adam decided to go to bed, but strangely Louis kept on reading. There was no artificial light around, so Louis kept on reading. How come?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see? What is it?

My friends called me Iron59 because my parents are a chemist and a mathematician. What is my real name?

A train leaves from point A for point B at 80 mph. After half an hour, another train leaves from point B for point A at 60 mph.

Which of the trains will be farther from point A when they meet ?

What does the below rebus riddle means?

Using eight eights and addition only, can you make 1000?

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?