ICOT – as I pointed out, it is counterintuitive to most people. That’s why I suggested thinking about the problem with 100 curtains (or doors), instead of 3.
You pick one. Chances are it’s not the right one.
They show 98 empty ones out of the remaining 99.
Isn’t it obvious that your best bet is to guess that the prize is behind the 99th? After all, they didn’t open 98 randomly. 99% chance that they opened all of the empty ones and left the one with the prize closed.
Same with 3.