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MathNet 2018-part-04 — 181 problems (EN–VI) Question 130

Math Olympiad Vault · MathNet 2018-part-04 — 181 problems (EN–VI)

Question 130

Let $a$, $b$, $c$ be three non-negative real numbers such that $a + b + c = 3$. Prove the inequality:
$$
\frac{a}{1 + b} + \frac{b}{1 + c} + \frac{c}{1 + a} \ge \frac{1}{1 + a} + \frac{1}{1 + b} + \frac{1}{1 + c}.
$$