MathCastle
ChallengeMediumHard Number Theory

Hard Number Theory · Medium problem

How many ordered triples (a,b,c)(a,b,c) of positive integers satisfy lcm⁡(a,b)=1000\operatorname{lcm}(a,b)=1000, lcm⁡(b,c)=2000\operatorname{lcm}(b,c)=2000, and lcm⁡(a,c)=2000\operatorname{lcm}(a,c)=2000?