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MathNet 2019-part-08 — 179 problems (EN–VI) Question 103

Math Olympiad Vault · MathNet 2019-part-08 — 179 problems (EN–VI)

Question 103

Let $S$ be the set of all positive factors of $6000$. What is the probability that a random quadruple $(a, b, c, d) \in S^{4}$ satisfies
$$
\operatorname{lcm}(\operatorname{gcd}(a, b), \operatorname{gcd}(c, d)) = \operatorname{gcd}(\operatorname{lcm}(a, b), \operatorname{lcm}(c, d))?
$$