Three bells Toll at intervals of 9,12 and 15 minutes. If they start to...
Understanding the Problem
When three bells toll at different intervals, we want to find out when they will next toll together after starting at the same time. The intervals are 9, 12, and 15 minutes.
Finding the Least Common Multiple (LCM)
To determine when the bells will toll together again, we need to calculate the Least Common Multiple (LCM) of their tolling intervals.
Steps to Calculate LCM
- **List the multiples of each interval**:
- Multiples of 9: 9, 18, 27, 36, 45, 54, 63, 72, 81, 90, 99, 108
- Multiples of 12: 12, 24, 36, 48, 60, 72, 84, 96, 108
- Multiples of 15: 15, 30, 45, 60, 75, 90, 105, 120
- **Identify the common multiples**:
- The common multiples from the lists above are 36, 72, 108, etc.
- **Determine the LCM**:
- The smallest common multiple is **36 minutes**.
Conclusion
After calculating the LCM, we find that the three bells will next toll together after **36 minutes**.
- **To recap**:
- The intervals are 9, 12, and 15 minutes.
- The LCM of these intervals is 36 minutes.
- Therefore, the bells will toll together again after **36 minutes**.