Find the next number in the series below

21 32 54 87 131 ?

Most people think of me as money. But when they find me in the water, they won’t get any money out of me. What am I?

Name one eight-letter word with 'kst' in the middle, 'in' the beginning, 'and' at the end.?

What 4-letter word can be written forward, backward or upside down, and can still be read from left to right?

A word I know,
Six letters contain,
Subtract just one,
And twelve is what remains.

John was so frustrated to be the suspect of being a sleeper terrorist that he shoot himself right between the eyes with a revolver in his toilet. The revolver and the bullets were accurate. Minutes later John walks out of the toilet unharmed.
How can this be possible?

I am white when I am dirty, and black when I am clean. What am I?

Manish has to secure 40% marks to pass his B.tech final exams.
He got just 40 marks and failed by 40-marks.

What is the maximum marks?

A cat had three kittens: Snophy, Topsy and Jorden. What was the mother's name?

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?