Actual explanation for Monty Hall. These are all the potential starting conditions and all the conditions after Monty removes a goat door.
In the first case, you already have the money.
In the second case, the money is behind another specific door.
In the third case, the money is behind the other specific door.
In the first case, Monty must remove a goat door, and if you switch, you get a goat.
In the second case, Monty must remove a goat door, and if you switch, you get money.
In the third case, Monty must remove a goat door, and if you switch, you get money.
Therefore there is a 2/3 chance that if you switch you get money.
SCD.