Question 1032804: The traffic light at three different road crossing changes after every 48 seconds, 72 seconds, and 108 seconds. If they start changing simultaneously at 8 am, after how much time they will change again simultaneously?
Answer by fractalier(6550)   (Show Source):
You can put this solution on YOUR website! We are asked to find a common multiple of 48, 72, and 108...
One way is to merely list the multiples of each and see the first number common in all three lists...like this...
48,96,144,192,240, etc.
72,144,216,288,360, etc.
108,216,324,432,540, etc.
The other way is to do a prime factorization and go from there...
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