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?

(In reply to consider the following by Jen)

Ok, Jen, but we assume that a "normal" clock, along its "life", will start to gain or loses time.

In fact, the original text was slightly altered, attending to a request of the "staff". The original text is : "while a normal clock may not be right...". 

Posted by pcbouhid on 2005-07-11 14:06:58