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Department of

Mathematics and Computer Science

Problem Of The Week


The Problem Of The Week (POTW) is a contest designed to challenge your thinking abilities through interesting mathematical problems and puzzles. The contest is open to everyone: students of all majors, faculty, high school students and the general public.


A new problem will be posted to this page every Monday at 3pm. The solution to a problem will be posted on Monday at 3pm, exactly one week after the posting of the problem.


Solutions can be submitted in one of two ways:

  • By email to: in the form of a PDF file, a scanned document or a Word document.
  • By dropping a hard copy at the Math/CS main office in Serra 133.

The day and time of submission are important in the scoring process (see scoring below). The deadline for submission is exactly one week after the posting of the problem.


The first 10 correct solutions will earn 10 points. The next 10 correct solutions will earn 7 points, and all subsequent correct solutions will earn 5 points. The n participants (n to be determined) with the highest scores at the end of the semester will be awarded a prize.

Problem #11

Week of April 14, 2014: Checkmate!

Two high school students entered a chess tournament composed of entirely USD students. Each contestant played once against each other contestant. The two high school students together scored a total of 8 points, and each USD student scored the same number of points as his or her schoolmates. (In the tournament, a contestant received 1 point for a win and half point for a draw.) How many USD students participated if the average score of USD students is higher than the average score of the two high school students?

Solution To Last Week's Problem


Top Scorers

  •  Name  Institution  Points
    Jesus Tonatiuh Otay Ranch HS 55
    Kevin O'Connor USD 55
    Craig Keuer Wheaton Warrenville South HS, Illinois 50
    Matthew Dudak Wheaton Warrenville South HS, Illinois 34
    Rommel Rico USD 27