I have teeth but i don't bite. Who Am I ?

I have Rs.50 and I spend it in the way as below.

There are three houses in a straight row. One is red, one is blue, and one is white. The red house is left of the middle. The blue house is right of the middle. Where's the white house?

What does below pictogram mean?

Which is faster, Heat or Cold ? Explain.

Luis Garavito killed Density x Volume.

Who is Luis Garavito ?

By including only four matchsticks in below picture, you have to make "Four Triangles And Two Squares"

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?

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 is a place where if I stand up straight, I will still be considered sideways.