I throw two dice simultaneously.

What is the probability of getting a sum as 9 of the two numbers shown?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?

A train full of passengers goes through a tunnel. When the train comes out from the other end, there is no single person on the train.

How did it happen?

What is common among 11, 69, and 88?

What is so fragile that saying its name breaks it?

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?

There is a square of a particular number which when doubled, becomes 7 more than its quarter.

Can you find the number?

Count the number of triangles in the picture below:

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?

One is to three as three is to five and five is to four and four is the magic number.
What is the pattern?