MathDB
n house in village - Iran NMO 2003 (Second Round) - Problem2

Source:

October 4, 2010
functiongeometryinequalitiesparallelogramtriangle inequalitycombinatorics proposedcombinatorics

Problem Statement

In a village, there are nn houses with n>2n>2 and all of them are not collinear. We want to generate a water resource in the village. For doing this, point AA is better than point BB if the sum of the distances from point AA to the houses is less than the sum of the distances from point BB to the houses. We call a point ideal if there doesn’t exist any better point than it. Prove that there exist at most 11 ideal point to generate the resource.