In a subterranean vault, a glowing orb counts down. It blinks every 3 seconds, chimes every 5 seconds, and flashes a light every 6 seconds. If it just performed all three actions simultaneously, how many seconds will pass before they happen together again?
30 seconds.
The event happens at intervals that are the least common multiple of 3, 5, and 6. The LCM of 3, 5, and 6 is 30.
About this riddle
Logic riddles give you a few facts and ask what must be true. List what you know, cross out what cannot be, and see what is left.
Difficulty: Medium. More like this: Logic riddles with answers or try Einstein's Logic Grid for a different kind of puzzle.
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