Mathematics
Three bells are ringing continuously at intervals of 30, 36 and 45 minutes respectively. At what time will they ring together again if they ring simultaneously at 8 a.m.?
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Answer
The required time interval is the LCM of 30, 36 and 45.
| 2 | 30, 36, 45 |
|---|---|
| 2 | 15, 18, 45 |
| 3 | 15, 9, 45 |
| 3 | 5, 3, 15 |
| 5 | 5, 1, 5 |
| 1, 1, 1 |
LCM of 30, 36 and 45 = 2 × 2 × 3 × 3 × 5 = 180 minutes.
Converting to hours: 180 minutes = 3 hours.
The bells ring simultaneously at 8 a.m. So they will ring together again at:
8 a.m. + 3 hours = 11 a.m.
Hence, the bells will ring together again at 11 a.m.
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