SOLUTION: One light house flashes every 10 seconds, and a second lighthouse flashes every 12 seconds. If they both flash at the same moment, how long will it be until they will flash togeth

Algebra ->  Numeric Fractions Calculators, Lesson and Practice -> SOLUTION: One light house flashes every 10 seconds, and a second lighthouse flashes every 12 seconds. If they both flash at the same moment, how long will it be until they will flash togeth      Log On


   

Question 842929: One light house flashes every 10 seconds, and a second lighthouse flashes every 12 seconds. If they both flash at the same moment, how long will it be until they will flash together again?
Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
Sixty seconds.

At a very low level you can simulate this way:

Starting at time 0,
10 sec______________12 sec
10__________________24
20__________________36
30__________________48
50__________________60
60___________

The first or smallest time point they have in common is 60 seconds.
This really is just like looking for a Lowest Common Denominator for fractions.