Living above a star, I do not burn
Eleven friends and they do not turn
I can just be visited in a sequence, not once or repeatedly
PQRS are my initials
Can you tell my name accurately?

What do you see in the image below

French Police inspects a room where there are no windows, no doors, no tables and is almost empty expect there is just a puddle of water. They found a dead man who obviously hung herself from the ceiling, but they are not able to figure out how this had happened.

John and Jacob entered the crime scene and easily able to solve the case.

How did the man die?

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?

I add 5 to 9 and get 2. The answer is correct, so what am I?

When I get multiplied by any number, the sum of the figures in the product is always me. What am I?

I had an infinite supply of water and 5 litres and 3 litres jars.

How would you measure exactly 4 litres in the least number of steps?

I have a hole in my back and legs I lack.
I live where I can’t breathe and I eat without teeth.
What am I?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

What is always in front of you but can’t be seen?