Originally Posted by Daithi
For question 9 I can explain the answer.
When you pick a door you have a 1/3 chance of being correct, and there is a 2/3 chance that one of the other two doors is correct. When the game show host opens one of the doors then that group of two doors still has a 2/3 chance of being correct, but now only one of those doors has that 2/3 chance of being the correct door.
That's pretty much it. The point is that when you first selected a door, you had a 66% chance of picking a goat. Once the host opens the door with a goat, then you now only have a 33% chance of picking another goat if you swap, and 33% chance of choosing the car. So you are twice as likely not to choose the goat if you swap. Clear as mud.
Anyway...Bilbo wins, so take it away Solihull man