This is a classic question loosely based on an old American Game Show. I'll provide the reference once we've finished the discussion and please don't "google" the answer as that will spoil it! As with all these discussions getting the correct answer isn't the point... it's to encourage you to think about the concepts and discuss.

"You are on a game show and you are shown 3 doors. Behind one door is a car and behind the other 2 are goats but you do not know which is which. You are asked to pick a door. Next the game show host, who know's what's behind the doors, opens one of the two doors that you did not choose revealing a goat. He then asks "Do you want to pick the remaining door or stick with your choice?" Is it to your advantage to switch?