Math Gold Medalist

Lor

2023 AMC 12B 

Problem 24

Suppose that $a$, $b$, $c$ and $d$ are positive integers satisfying all of the following relations.

\[abcd=2^6\cdot 3^9\cdot 5^7\]\[\text{lcm}(a,b)=2^3\cdot 3^2\cdot 5^3\]\[\text{lcm}(a,c)=2^3\cdot 3^3\cdot 5^3\]\[\text{lcm}(a,d)=2^3\cdot 3^3\cdot 5^3\]\[\text{lcm}(b,c)=2^1\cdot 3^3\cdot 5^2\]\[\text{lcm}(b,d)=2^2\cdot 3^3\cdot 5^2\]\[\text{lcm}(c,d)=2^2\cdot 3^3\cdot 5^2\]

What is $\text{gcd}(a,b,c,d)$?

$\textbf{(A)}~30\qquad\textbf{(B)}~45\qquad\textbf{(C)}~3\qquad\textbf{(D)}~15\qquad\textbf{(E)}~6$

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   Solution