dap1@ihlpf.UUCP (08/28/83)
#N:ihlpf:6200013: 0:1005
ihlpf!dap1 Aug 27 17:32:00 1983
Here's a variation on a problem I heard long ago (I don't recall where):
A judge sentanced three men and placed them in cells. The stipulations
of the sentance were that at the end of the week, the judge would pull
one prisoner's name from a hat and that prisoner would be executed. The
other two would be set free. The prisoner in the third cell reasons as
follows:
Only one of us will die, so either the prisoner in cell A will live or
the prisoner in cell B will live. Suppose the prisoner in cell A will
live. Then I have a 1/2 chance of death. On the other hand, suppose the
prisoner in cell B will live. I still only have a 1/2 chance of living.
Thus, in either of these cases, I only have a 1/2 chance of living!
It's not TOO hard to figure out where his reasoning went wrong, but it makes
for an interesting question for those unacquainted with probability.
Darrell Plank
8/27/83