Question 290333: 16.Two bells ring at 8:00 am. For the remainder of the day, one bell rings every half hour and the other rings every 45 minutes. What time will the bells ring again together?
Found 2 solutions by brucewill, MathTherapy:
Answer by brucewill(101)   (Show Source):
You can put this solution on YOUR website! Sort of a non-algebraic, but logical answer: Enumerate the times.
First will ring at 0830, 0900, 0930, 1000, 1030, 1100.
Second will ring at 0845, 0930, 1015, 1100.
Therefore, they will both ring togeter at 11am.
Answer by MathTherapy(10549)  (Show Source):
You can put this solution on YOUR website! 16.Two bells ring at 8:00 am. For the remainder of the day, one bell rings every half hour and the other rings every 45 minutes. What time will the bells ring again together?
Since both bells ring at 8:00 AM, it follows that the next time they ring at the same time, the same amount of minutes would've passed from the time they both rang at 8:00 AM.
This next time would be the LCM of both 30 and 45 minutes that would represent the exact amount of minutes to the time that they will again ring at the same time. Therefore, we find the LCM of 30 and 45, which is:  minutes.
This means that 90 minutes after 8:00 AM, they will ring together again, and 90 minutes after 8:00 AM is  .
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