It is well known that a stopped clock gives the exact time twice a day, while a clock that gains or loses time may not be right more than once over a period of months.

My clever father adjusted his clock to give the correct time at least twice a day, while running at the normal rate.

Assuming he was not able to set it perfectly (a reasonable assumption) how did he do it?

I assume what the creator of this puzzle has in mind is to set the clock to run backwards.

Another possibility that comes to mind is to interchange some of the hands.  Putting the minute hand on the second's post and leaving the hour hand alone would make the clock correct many times an hour.

One could also combine these two ideas.

Posted by Jer on 2005-06-24 12:02:26