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MathNet 2026 — Part 09 Question 98

Math Olympiad Vault · MathNet 2026 — Part 09

Question 98

Let $a \leq b \leq c \leq d$ be real numbers such that

$$
a+b+c+d=0 \quad \text{ and } \quad \frac{1}{a}+\frac{1}{b}+\frac{1}{c}+\frac{1}{d}=0
$$

Prove that $a+d=0$.