BDMO REGIONAL 2015
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Please don't post problems (by starting a topic) in the "X: Solved" forums. Those forums are only for showcasing the problems for the convenience of the users. You can always post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.
Please don't post problems (by starting a topic) in the "X: Solved" forums. Those forums are only for showcasing the problems for the convenience of the users. You can always post the problems in the main Divisional Math Olympiad forum. Later we shall move that topic with proper formatting, and post in the resource section.

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BDMO REGIONAL 2015
Help me to solve this......
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Re: BDMO REGIONAL 2015
Note that the distinct numbers are repeated according to their intrinsic values.Find their summation noticing that the summation of a distinct pair is equal to the square of that distinct pair.Find the remainder which shows that the division upon a number by 3 leaves the same remainder as it does upon the division of the summation of that number by 3.It is easy to prove this fact using modular arithmetic.