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2009 UNCO Math Contest II Problems/Problem 2

Revision as of 16:47, 19 October 2014 by Timneh (talk | contribs) (Created page with "== Problem == (a) Let <math>Q_n=1^n+2^n</math>. For how many <math>n</math> between <math>1</math> and <math>100</math> inclusive is <math>Q_n</math> a multiple of <math>5</mat...")
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Problem

(a) Let $Q_n=1^n+2^n$. For how many $n$ between $1$ and $100$ inclusive is $Q_n$ a multiple of $5$?

(b) For how many $n$ between $1$ and $100$ inclusive is $R_n=1^n+2^n+3^n+4^n$ a multiple of 5?


Solution

See also

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