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3 bells ring at intervals of 3hrs, 4hrs and 16hrs respectively. If they have rung together once today, what day in the future will they ring together next?

Solution

✅ Correct Option: 4

The bells will ring together again at the LCM (Least Common Multiple) of their intervals.


Prime factorization of each interval:

3=313 = 3^1

4=224 = 2^2

16=2416 = 2^4

The LCM takes the highest power of each prime factor:

Highest power of 2=24=162 = 2^4 = 16

Highest power of 3=31=33 = 3^1 = 3

LCM=16×3\text{LCM} = 16 \times 3

LCM=48\text{LCM} = 48 hours


Converting to days:

48 hours24 hours/day=2 days\dfrac{48 \text{ hours}}{24 \text{ hours/day}} = 2 \text{ days}


The bells will ring together again in 22 days from today.

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