Question:

Let say you have a revolver with six chambers. There are two bullets in the gun. The bullets are
located in two chambers next to each other. You now want to play Russian roulette. You spin
the barrel so that you don’t know where the bullets are and then pull the trigger. We assume
that you don’t kill yourself with this first attempt. Now assuming that you want to maximize
the chance of not killing yourself is it better to spin the barrel or not before you pull the
trigger a second time?

Answer:

If you spin the barrel you have a two in six or a one in three chance that the first pull of the
trigger will kill you.

Further there are four empty chambers in the revolver but only one of them is followed by a
chamber containing a bullet. So if you spin the barrel and manage to survive the first pull of
the trigger then the chances that the next pull will kill you is one in four.

This means that you should not spin the barrel before your second attempt if you want
to maximize your chances of not killing yourself.

After surviving two pulls of the trigger without spinning the barrel the odds become one in
three again, and it doesn’t matter whether you spin or not.

After surviving three pulls of the trigger without spinning the barrel the odds become 1 in 2.

After surviving four pulls of the trigger without spinning the barrel then the next time you
pull the trigger you will most definitely die.