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MathNet 2014 Question 84

Math Olympiad Vault · MathNet 2014

Question 84

Let $a$, $b$, $c$ be positive real numbers such that $a + b + c = 1$. Prove that
$$
\frac{7 + 2b}{1 + a} + \frac{7 + 2c}{1 + b} + \frac{7 + 2a}{1 + c} \geq \frac{69}{4}.
$$
When does equality hold?