n stationary people
Source: Canada National Mathematical Olympiad 1987 - Problem 4
October 3, 2011
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Problem Statement
On a large, flat field people are positioned so that for each person the distances to all the other people are different. Each person holds a water pistol and at a given signal fires and hits the person who is closest. When is odd show that there is at least one person left dry. Is this always true when is even?