How many times can you subtract the number two from the number fifty?

You knock a Table over in the library, and suddenly 20 eyes are looking at you.

Fate has decided that you will only be pleased to meet me when you need me

Maybe that is why, when I am working, I start working

However annoying I may be to the regulars, the little ones are always inspired

I will always be waiting if you try to reach me

How many of you can guess my name, let me see

I don't get anymore wetter, no matter how much rain falls on me.

What has one letter and starts with an E?

A person was found dead on a big green land with no trees or buildings around. When the police arrived, they found a piece of rock lying next to him and the man was wearing clothes comprising of red, blue and yellow colours.

Can you tell who the person is and what was the cause of death?

I live in a bowl. I can swim. I have a tail. I also have fins and big eyes. What am I?

The more of this there is, the less you see. What is it?

What demands an answer, but asks no questions

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?