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

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

What has a ring but no finger?

A King wants to send the diamond ring to his girlfriend securely. He got multiple locks and their corresponding keys. His girlfriend does not have any keys to these locks and if he sends the key without a lock, the key can be copied in the way. How can King send the ring to his girlfriend securely?

What can run but never walk, have a mouth that never speaks, have a head that never weeps, and have a bed but never sleeps?

The first box has two white balls. The second box has two black balls. The third box has a white and a black ball.

Boxes are labeled but all labels are wrong!

You are allowed to open one box, pick one ball at random, see its colour and put it back into the box, without seeing the colour of the other ball.

How many such operations are necessary to correctly label the boxes?

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 have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

There are 2 people near the river and both of them want to get on the other side. The boat can only take one of them. But they got across.
How?

I possess a head

I flaunt a tail

But I don't have mouth or legs

Can you find out who I am?