What does the following BrainBat signifies?

ABCDEFGHIJKLMNOPQRSTUVWYZ

QQQQQQQQQQQQQQQQQQQQQQQQQ.

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

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?

Solve The below Equation:

ALFA + BETA + GAMA = DELTA

Find The Next Number in the series:

12 13 15 17 111 113 117 119 123 ?

When you say goodbye, I am what you need to tie.
I come as a couple and go wherever you run.
Who 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 can you hold in your right hand, but never in your left hand?

The centre of the third figure is empty. What digit should fit inside?

Count the number of triangles in the picture below: