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

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

Solve the puzzle by telling what does below picture means.

To tease, King Akbar told his most clever advisor Birbal to give his daughter one thing that she can eat when hungry, drink if she feels thirsty and can burn if she feels cold. King Akbar was shocked when Birbal gave Akbar's daughter one such thing that satisfies all of the above.

What did Birbal give to Akbar's daughter?

What work can one never finish?

I have a head like a cat and feet like a cat, but I am not a cat. What am I?

What will you call your mother's brother's brother-in-law?

It comprises roots which nobody sees,
Much taller than those trees,
Up and up it goes,
Still it never grows?

What is the fewest number of coins that would be required in order to make sure each and every coin touches exactly three other coins?

A man in a car saw a Golden Door, Silver Door and a Bronze Door. What door did he open first?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?