We have 3 doors.
Two door contains a goat and one contain a prize,
say, BMW car.
Now, you have to choose one of the door,
Wait, the game is not finished yet...
Then, one of the door containing goat is opened
and a reconsider chance (swap) is given to change the choosen door.
Then result are declared.
Well, lets check if you are lucky enough to win a BMW car...