MathDB
Six nonnegative numbers [2011.II.9]

Source:

March 31, 2011
AMCAIMEnumber theoryrelatively prime

Problem Statement

Let x1,x2,,x6x_1,x_2,\dots ,x_6 be nonnegative real numbers such that x1+x2+x3+x4+x5+x6=1x_1+x_2+x_3+x_4+x_5+x_6=1, and x1x3x5+x2x4x61540x_1x_3x_5+x_2x_4x_6 \geq \frac{1}{540}. Let pp and qq be positive relatively prime integers such that pq\frac{p}{q} is the maximum possible value of x1x2x3+x2x3x4+x3x4x5+x4x5x6+x5x6x1+x6x1x2x_1x_2x_3+x_2x_3x_4 + x_3x_4x_5 + x_4x_5x_6 + x_5x_6x_1 + x_6x_1x_2. Find p+qp+q.