MathDB
Jbmo 2011 Problem 3

Source: Jbmo 2011

June 21, 2011
geometryrhombussymmetryratiocombinatorics unsolvedcombinatorics

Problem Statement

Let n>3n>3 be a positive integer. Equilateral triangle ABC is divided into n2n^2 smaller congruent equilateral triangles (with sides parallel to its sides). Let mm be the number of rhombuses that contain two small equilateral triangles and dd the number of rhombuses that contain eight small equilateral triangles. Find the difference māˆ’dm-d in terms of nn.