IMO-2009-1

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Tahmid Hasan
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IMO-2009-1

Unread post by Tahmid Hasan » Wed Feb 08, 2012 6:17 pm

Let $n$ be a positive integer and let $a_1, . . . , a_k (k \geq 2)$ be distinct integers in the set ${{{1, . . . ,n}}}$ such that $n$ divides $a_i(a_{i+1} −1)$ for $i = 1, . . . ,k−1$. Prove that $n$ does not divide $a_k(a_1−1)$.
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*Mahi*
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Re: IMO-2009-1

Unread post by *Mahi* » Wed Feb 08, 2012 6:26 pm

If anybody need a hint...
Take mod...$m|a-b \Rightarrow a\equiv b (\text{mod }m)$
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Nur Muhammad Shafiullah | Mahi

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