SOLUTION: Two light house flash their lights every 20 seconds and 30 seconds respectively. Given that they flashed together at 8:00 P.M.. When will they next flash together?

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Question 765931: Two light house flash their lights every 20 seconds and 30 seconds respectively. Given that they flashed together at 8:00 P.M.. When will they next flash together?
Answer by josmiceli(19441) About Me  (Show Source):
You can put this solution on YOUR website!
Find the smallest number that both
20 and 30 divide into evenly
+120+%2F+20+=+6+
+120+%2F+30+=+4+
but,
+60%2F20+=+3+
+60%2F30+=+2+
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In 60 seconds, or 8:01 PM, they both
flash together