How can you take 2 from 5 and leave 4?

Can you count the number of triangles in the given figure?

I have lakes with no water, mountains with no stone and cities with no buildings. What am I?

P is the father of Q and S is the son of R. T is the brother of P and has a daughter U. If R is the sister of P, then what is the relation between U, Q and S?

If your uncle’s sister is not your aunt, what relation is she to you?

I shave every day, but my beard stays the same. What am I?

Name a key which is hardest to turn.

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.

In the city of Brain Teasers, 5% of people do not list their phone numbers. Now if we select random 100 people from the phone directory, then how many people selected will have unlisted phone numbers?

What has lots of eyes, but can’t see?