Sam and martha are the local names for two lighthouses that guard a particularly dangerous part of the coast. sam blinks every 12 seconds, and martha blinks every 8 seconds they blink together at midnight. how many seconds will pass before they blink together again?

Write the repetitive numbers in order as many times as it takes until both are the same number. (what I mean is order the number in order by increasing (ex: 25, 50, 75, etc.))
Sam's blinks: 15, 30, 45, 60, 75, 90, 105
Martha's blinks: 25, 50, 75, 100, 125, 150, 175
They both have 75, so that is the amount of seconds. ( 75 seconds)