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

When Jack was six years old he hammered a nail into his favourite tree to mark his height. Ten years later at age sixteen, Jack returned to see how much higher the nail was. If the tree grew by five centimetres each year, how much higher would the nail be?

What do you think with the below Picture ?

A new Engineering building containing 100 offices had just been completed. John was hired to paint the numbers 1 to 100 on the doors. How many times will John have to paint the number nine (9)?

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.

I was speeding and ran through a stop sign, yet two traffic officers who were there do nothing about it.

why?

By what process could you make a 'Tea-Table' into food?

"That Restaurant always remains crowded. This is the reason why nobody goes there".

Can you find a flaw in this statement?

What's the only room from which no one can enter or leave

I look at you, you look at me, I raise my right, you raise your left. What am I?