Question

Four bells strike at intervals of 6, 8, 9 and 12 minutes. An alarm is set in a mobile phone such that it alarms after every hour. It was noticed that all the bells struck simultaneously when mobile phone alarmed at 10:00 am. At what time all the bells will strike together with the alarm?

Answer 1

Answer:

LCM of 6, 8, 9 and 12 = 72

But the bells ring along with the alarm which rings every 60 minutes.

So, LCM of 72 and 60 = 360

Thus, after 360 minutes = 6 hours, the bells with ring together with the alarm.

Time = 10:00 am + 6:00 hrs = 4:00 pm

ANSWER = 4:00 PM