Comment by drfuchs

I found the easiest way to convince non-mathematical types is by suggesting we do the million-door version: “Ok, pick a door between 1 and 1,000,000. We’ll call that door N. Now, I’ll open 999,998 bad doors. So, now only door N and door 223,205 are still closed, and one of them has the good prize. Want to keep door N, or swap?”