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MathNet 2009-part-01 — 175 problems (EN–VI) Question 43

Math Olympiad Vault · MathNet 2009-part-01 — 175 problems (EN–VI)

Question 43

Let $a$, $b$, $c$ be positive numbers such that $a$, $b$, $c \gt 1$ and
$$
\frac{1}{a} + \frac{1}{b} + \frac{1}{c} = 2.
$$
Prove that $\sqrt{a+b+c} \ge \sqrt{a-1} + \sqrt{b-1} + \sqrt{c-1}$.