Heard of The Monty Hall problem?

It’s a famous Maths problem that originates from a game show in America. In the game show the contestant is shown THREE doors. He or she is told that behind two doors there is a Goat and behind one of the doors is a brand new luxury car.

The contestant chooses a door. The quiz compere now opens one of the remaining doors to reveal a Goat behind it and asks the contestant whether or not he or she wishes to swap their first choice door for the one remaining door.

What should they do?

Many great minds debated this when it was first publicised and many people still believe that it makes no difference as the odds of getting a goat (to coin a phrase) are now 50:50. Nothing could be further from the truth – the odds are overwhelmingly in favour of changing your decision. Here is why:

Outcome one: You choose the car, get shown a goat, change door and get…the other goat. LOSE

Outcome two: You choose goat 1, get shown goat 2, change and get…the car. WIN

Outcome three: You choose goat 2, get shown goat 1, change and get…the car. WIN

Two Wins to One Lose. So…always change.

Which brings me to Deal Or No Deal. I recently played on one of the games fruit machines at a service station whilst killing time between appointments. I got through to the deal or no deal round…finally ending up with three boxes. They were either: 50p, £10 or £75 and I had the option of changing or taking an offer from the banker of £21. Well my instincts said take the offer but I remembered Monty Hall and I had a “glimpse” button available. The machine showed me the £10 box! I immediately took the option of switching and ignored the bankers offer…

…I won £75!

I now have plenty of cash for car parks!