Henry Ernest Dudeney/Modern Puzzles/99 - The Rejected Gun/Solution

by : $99$

 * The Rejected Gun

Solution
This is an instance of the Fencepost Mistake.

Let it be assumed that the firing a single shot is an instantaneous action.

Then to fire $60$ shots at one per minute will take $59$ minutes.

It must be the case that the testing facility observed that over the course of $1$ hour, $60$ shots were fired, whereas in fact it would be expected for there to be $61$ shots fired.