This is, I hope, a fun quiz.

Tonight I was at a meeting in a room that has two motel-style
AC/heating units in the wall, under the windows. They are 40 years
old and have worked without problem afaik all these years.

Tonight, the fan in one of them started making a scraping noise some
of the time, long scrapes when they happened

Sometimes it ran fine, sometimes it scraped, and sometimes it caught
on something and stopped altogether, but only for a couple minutes.

Everyone was leaving this evening and no one was expected back for 24
hours.

What are the odds that the fan would catch on the shroud and stay
stuck?

The odds that when it did that, the motor would overheat?

The odds that there isn't thermal protection in an AC fan motor that
is 40 years old?

The odds that the thermal protection wouldn't work?
(These last two are in the negative so that all the questions ask
about bad results.)

The odds that if the thermal protection didn't work, the fan would
catch on fire?

Alterntively, what are the cumulative odds, from beginning to end,
that this AC will catch on fire in the next 24 hours?

What are the odds that if there was a fire, it would be hot enough to
set fire to something outside the AC**?


**Yeah, we could move everything, but this is just a questionairre.
What we actually did is turn the AC off.



The building is 40 years old now, it's sold and will be torn down when
the new owner gets around to it. Until then, we're renting the
building we used to own.