Can you identify if it's a murder or a suicide ?

Double it and multiply it by 4. Then divide it by 8 and you’ll have it once more. What number is it?

How is the moon similar to a dollar?

It is a six-letter word.
The first four letters are me.
The second and last letters are the same.
The fourth second and last letter is payment.

Who is it?

John was drowned by he was not wet. How?

Look at the below sequence of letters and tell us what the next letter should be:

O T T F F S S ?

Two in a corner, one in a room, zero in a house, but one in a shelter. What is it?

You are trapped in a room with two doors. One leads to certain death and the other leads to freedom. You don't know which is which.
There are two robots guarding the doors. They will let you choose one door but upon doing so you must go through it.
You can, however, ask one robot one question. The problem is one robot always tells the truth, the other always lies and you don't know which is which.
What is the question you ask?

It can't be seen, can't be felt, can't be heard, and can't be smelt.
It lies behind stars and under hills, And empty holes it fills.
It comes first and follows after, Ends life, and kills laughter.
What is it?

Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?