What numbers should go on the bottom line?
3 6 9 15
8 2 10 12
11 8 19 27
19 10 29 39
? ? ? ?

There are three boxes on a table. One of the box contains Gold and the other two are empty. A printed message contains in each box. One of the message is true and the other two are lies.

The first box says "The Gold is not here".

The Second box says "The Gold is not here".

The Third box says "The Gold is in the Second box".

Which box has the Gold?

There are nine dots in the picture that has been attached with this question. Can you join all the dots by drawing four straight lines without picking up your pen?

What type of tree can I carry in my hand?

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.

What can you hold in your right hand, but never in your left hand?

The picture shows the dice results in each couple of throws. If they are actually following a pattern, can you find out the missing one?

Take away the whole and some still remain. What is it?

There is one thing that goes round the house and also inside the house but never even share a brief touch. What is it?

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