GATE 2021 ME (ME2) – Question 3
A digital watch X beeps every 30 seconds while watch Y beeps every 32 seconds. They beeped together at 10 AM. The immediate next time that they will beep together is
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: (A) 10:08 AM
Explanation
The next coincidence occurs after the least common multiple of 30 and 32. Their gcd is 2, so $LCM=30(32)/2=480$ seconds.
480 seconds is 8 minutes, giving **10:08 AM (A)**.