An electronic device makes a beep after every 15 minutes. Another device makes a beep after every 20 minutes. They beeped together at 6 a.m. At what time will they next beep together?
The LCM of the time intervals of the beeps will give the time when the electronic devices will beep together.
LCM of 15 and 20:
Required time = 5 × 3 × 2 × 2
= 60 min
So, they will beep simultaneously after 60 min or 1 h.
∴ They will beep together again at 7:00 a.m.
RS Aggrawal (2020, 2021)