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Concord Academy

Math Club


Each week (time and place TBD soon) we meet to prepare for math competitions, enjoy some recreational mathematics, or work on logic puzzles.  Everyone is welcome to attend every week or just once if you want to check it out.




Student Officers:

Jason He & Raphi Kang.


Faculty or Staff Advisors:

Shawn Bartok


Recent work:

We plan to attend the Harvard MIT Math Tournament in November!  Please email any of the faculty advisor(s) or cohead(s) with questions or for more information.



List of summer math camps US​ (word doc)​​​

List of summer math camps in US (pdf)


Current Problem of the Fortnight:

When children play games where they want to decide which person will be "it" they often default to using dukes (a counting rhyme).  For example, eeny, meeny, miny, moe is often used.  To simplify this we will assume that all people sit in a circle.  Then person 1 stays, person 2 leaves, person 3 stays, etc…  They continue to stay and leave alternately until there is only one person remaining.  This final person is “it.”

For example, with four people person 1 would stay, then person 2 would leave, then person 3 would stay, then person 4 would leave.  This brings us back to person 1 who would stay, then person 3 would leave.  This would result in person 1 being "it" for the game.  

I don't like to be "it" during games so I want to be somewhere strategic in the circle so that I will not end up being "it."  However, I don't want anyone to catch on that I'm cheating so I will sit where the last person who leaves will be to avoid suspicion.  In the example of four people the last person to leave was person 3.

Part A:  With 9 people where should I sit so that I leave last?
Part B:  With n>2
 people where should I sit so that I leave last?

Solutions are due by 3:15 PM on 10/31.  Feel free to direction solutions and questions to Shawn (office 212 in MAC)