Question 659894
Imagine a planet with 3 moons.  Moon A completes its revolution around the planet in just 7 hours.  Moon B takes 12 hours to orbit the planet, and Moon C takes 16 ours.  Supose that at noon on May 13 they are all alined up.  When will they next all be lined up in that position?
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It's the least common multiple of the 3 times.
= 336 hours = 2 weeks
--> noon on May 27