@mmcp42 I was hoping for a bar brawl ]

The answer is very counter intuitive; There before me sits two ashtrays, one of which had a gold krugerrand beneath it. It feels like the odds are the same, 50:50, as to which ashtray the coin is under.

In fact by changing my choice I double the chance of getting the coin.

The simplest way I can describe this is that initially, when there were 3 ashtays, the odds were equal 1:3 that the coin was under any particular ashtray.

I made a random choice, so there was a 1:3 chance the coin was under the ashtray I picked.

After I made my choice one of the other ashtrays was turned over to show it was empty. Doing this did not change the odds of the coin being under my ashtray. However it did change the odds of it being under the remaining unturned ashtray which then became 2:3.

As a result by changing my mind and chosing the other ashtray I will double my chance of getting the coin.