Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

To attend world science seminar, A famous chemist from Mexico visit
London. In the lab, the scientist was killed and his six assistants were under suspicion of killing the chemist.
Name of six assistants: Austin, Wayne, Dege, Oscaru, Lingard, and Rojo.
He left a note "76-20-44 79-16-22-7"

A local detective Jack was called to solve the case,

After reading the note, Jack instantly asked the police to arrest the murderers.

Who are the murderers?

Take away the whole and some still remain. What is it?

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

It is always ahead of me yet I can never see it. What is it?

Can you name an animal whose killing cannot be performed without spilling your own blood?

A man calls his dog from the opposite side of a river. The dog crosses the river without a bridge or a boat and manages to not get wet. How is this possible?

What came first, the chicken or the egg?

Can you find out which number multiplied by itself will give the output as 12345678987654321?

Many have heard it, but nobody has ever seen it, and it will not speak back until spoken to. What is it?