How many times can you subtract the number 5 from 25?

I am the beginning of everything, the end of everywhere. I'm the beginning of eternity, the end of time and space. What am I?

If 21x = 79x, what is the value of x?

There are people and strange monkeys on this island, and you can not tell who is who (Edit: until you understand what they said - see below). They speak either only the truth or only lies.
Who are the following two guys?
A: B is a lying monkey. I am human.
B: A is telling the truth.

Who is that with a neck and no head, two arms and no hands? What is it?

There is something which you can be arrested for attempting but not for successfully completing.

You need to remove two matchsticks to make the below equation true. Can you do it ?

Rearrange the letters in "new door" to make one word.

How can you write nineteen in a manner that if we take out one, it becomes twenty?

Can you find out the missing number?

? 4 5 3 5

9 5 7 10 3