Complete the table series riddle by finding the number that can replace "??".

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

I can sizzle like bacon,
I am made with an egg,
I have plenty of backbone, but lack a good leg,
I peel layers like onions, but still remain whole,
I can be long, like a flagpole, yet fit in a hole.

I am not alive, but I grow; I don't have lungs, but I need air; I don't have a mouth, but water kills me. What am I?

Why do people go to bed?

Why do you find that most of the buildings are deprived of the 13th floor?

I am looking for a word that change both gender and number when i add the letter 'S'.

What Word am I Looking For ?

You are given with the following sum. Each of the letters can be decoded as a digit. If we tell you that D = 5, then can you solve it entirely?

DONALD
+GERALD
=ROBERT

John is the son of Jacob.
So,
Jacob is the_____of John's father?

There is a shop where written:
Buy 1 for $1
10 for $2
100 for $3
I needed 999 and still only paid $3. How could this be financially viable for the shop-keeper?