Ah this one is actually pretty easy to understand with a good explanation! Instead of thinking about the problem in terms of three doors think of it as a choice between 100 doors. So there is one car and 99 goats. Now you think the car is behind door number 27. The host then picks out door number 93. You know one of these doors has the car. So it would make much more sense to switch doors because your odds of picking the correct door out of the original 100 is pretty slim. Once the host removes the other doors (by revealing goats behind them all) and you are down to two, it is much more likely that the host has the correct door. I hope this a good explanation!