Three bells ring at intervals of 12, 16 and 18 seconds. If they ring together now, after how many seconds will they next ring together?

💡 Solution & Explanation

The bells ring together again after a time that is a multiple of all three intervals, and the first such time is the LCM. LCM of 12 and 16 is 48, and LCM of 48 and 18 is 144. So the bells ring together again after 144 seconds. Adding the intervals or multiplying them gives a common time, but not the first one.