What goes up but never comes down?

What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

John replied, when asked how old he was. In 2 years he will be twice as old as he was five years ago.' How old is he ?

I know a country, If you remove the last alphabet of its name, it will become a part of your body. Do you name it?

If an earthquake is 1 point higher on the Richter Scale than another earthquake which is actually 10 times stronger, how much stronger would an earthquake be if it was just half a point higher on the Richter scale?

Find the next number in the series.
1 10 24 43 67 ?

John was drowned by he was not wet. How?

Can you count the number of quadrilaterals 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?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?