Two alarm clocks ring their alarms at regular intervals of 50 seconds and 48 seconds. If they first beep together at 12 noon, at what time will they beep again ?
12:10 P.M
12:12 P.M
12.11 P.M
None of these
They will ring together after,
LCM of 48 and 50 secs.
$48=2 * 2 * 2 * 2 * 3$
$50=2^* 5^* 5$
$LCM=2 * 2 * 2 * 2 * 3 * 5 * 5=1200 secs$
=20 min
They will beep together at 12:20