Three doctors said that Bill was their brother. Bill says he has no brothers. How many brothers does Bill actually have?

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

You need to move three matchsticks to form three squares. Can you do it?

The more you take me, the more you leave me behind.
Who Am I?

There was an aeroplane crash, every single person died, but two people survived. How is this possible?

Two boys wish to cross a river. The only way to get to the other side is by boat, but that boat can only take one boy at a time. The boat cannot return on its own, there are no ropes or similar tricks, yet both boys manage to cross using the boat.

How?

If 1+9+8=1, what is 2+8+9?

What is the centre of gravity?

I am taken from a mine and shut up in a wooden case, from which I am never released, and yet I am used by almost every person. What am I?

Rob is taller than Edwin, and Jurgen is shorter than Rob.
Of only one of the following statements, we now certainly know it is correct:

A.Edwin is taller than Jurgen
B.Jurgen is taller than Edwin
C.It cannot be determined if Jurgen or Edwin is the tallest.