Two alarm clocks ring their alarms at regular intervals of 60 seconds and 90 seconds. If they first beep together at 12 noon, at what time will they beep again together for the first time?

Q. An alarm beeps every $3$ hour, and another alarm beeps every $12$ hour. If they beep at $00:00$ hour, at what time will they again beep together?

Q. Three alarms clocks rings at interval at $4,12$ and $20$ minute respectively. If they start ringing together after how much time will they next ring together?

Q. an electric device makes a beep every 60 seconds. another device makes a beep every 62 seconds. they beep together at 10:30 am. find the time they will make a beep together at the earliest

Q. An electric device make a beep every 60seconds.Another device makes a beep after 62seconds .They beeped together at 10:00am.Find the time when they will next time make a beep together at the earliest