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lowest possible value of the expression

Source: Middle European Mathematical Olympiad T-1

September 21, 2014
inequalitiesinequalities proposed

Problem Statement

Determine the lowest possible value of the expression 1a+x+1a+y+1b+x+1b+y \frac{1}{a+x} + \frac{1}{a+y} + \frac{1}{b+x} + \frac{1}{b+y} where a,b,x,a,b,x, and yy are positive real numbers satisfying the inequalities 1a+x12 \frac{1}{a+x} \ge \frac{1}{2} 1a+y12\frac{1}{a+y} \ge \frac{1}{2} 1b+x12 \frac{1}{b+x} \ge \frac{1}{2} 1b+y1. \frac{1}{b+y} \ge 1.