Difference between revisions of "2001 IMO Problems/Problem 4"

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{{IMO box|num-b=3|num-a=5|year=2001}}
[[Category:Olympiad Combinatorics Problems]]
[[Category:Olympiad Combinatorics Problems]]

Revision as of 09:29, 15 October 2008


Let $n_1, n_2, \dots , n_m$ be integers where $m$ is odd. Let $x = (x_1, \dots , x_m)$ denote a permutation of the integers $1, 2, \cdots , m$. Let $f(x) = x_1n_1 + x_2n_2 + ... + x_mn_m$. Show that for some distinct permutations $a$, $b$ the difference $f(a) - f(b)$ is a multiple of $m!$.


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See also

2001 IMO (Problems) • Resources
Preceded by
Problem 3
1 2 3 4 5 6 Followed by
Problem 5
All IMO Problems and Solutions
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