Question

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 _____.

1. 10.42 AM
2. 10.00 PM
3. 10.08 AM
4. 11.00 AM

Answer 1

Correct Answer - Option 3 : 10.08 AM

Concept:

The Watched will beep together at the time of their Least Common Multiple (LCM).

Calculation:

Given:

Watch X beeps at = 30 sec

Watch Y beeps at = 32 sec

They beep together at = 10.00 AM

LCM of (30 & 32) = 480 sec

And X and Y will beep together after 480 sec or 8 minutes.

So Next beep time = 10.08 AM