Problem
of the
Week
My apologies for the lack of new problems the last two weeks.  We changed computer systems recently and the resulting confusion made the last two problems inaccessible.   

This will be my last Problem of the Week.  My responsibilities on campus make it difficult for me to keep up with the problems, solutions and correspondence, so after running this site for ten years, I have decided to retire it.  I will continue to maintain the archive of past problems and solutions.  It has been great fun for me to provide you with some mathematical diversions.  There are now many other websites of a similar nature.  Please enjoy them.  

PROBLEM 278

A pool shark was playing pool on a table with a 15° corner.  She hit a ball parallel to one of the sides (see the figure on the left)  into the corner of the table and noticed that, after bouncing off the bumpers a few times, the ball returned to the position from which she initially hit it.  How many times did the pool ball bounce off the bumpers before it returned?  (Remember your basic physics:  The angle at which the ball rebounds equals the angle at which it enters the bumper.) 

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ã2007 Alberto L. Delgado