What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

Can you find a pattern and the missing number in the series given below?

100, 155, 258,? , 584, 819.

John killed hundreds of people mercilessly and yet the police were not able to put her behind the bars. Why?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3

Use only one mathematical symbol and all numbers (0-9) to get a sum of 99

A network of 20 x 10 squares is given to you.

Can you calculate how many unique squares and rectangles can be formed combining two or more individual squares ?

Can you replace the X (both small and big x) with the numbers between 1 to 19 such that all the rows of 3 numbers between X (big x) sum to 23?

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?

There are 3 apples in the basket and you take away 2. How many apples do you have now?