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MathNet 2026 — Part 03 Question 182

Math Olympiad Vault · MathNet 2026 — Part 03

Question 182

Let $x$, $y$, $z$ be positive real numbers. 1. If $x + y + z \geq 3$, is it necessarily verified that $\frac{1}{x} + \frac{1}{y} + \frac{1}{z} \leq 3$? 2. If $x + y + z \leq 3$, is it necessarily verified that $\frac{1}{x} + \frac{1}{y} + \frac{1}{z} \geq 3$?