Bissoy.com
Doctors Medicines MCQs Q&A

Three bells ring at intervals of 48, 60 and 90 minutes respectively. If all the three bells chime together at 10 AM, at what time will all the three chime again that day?

Three bells ring at intervals of 48, 60 and 90 minutes respectively. If all the three bells chime together at 10 AM, at what time will all the three chime again that day? Correct Answer 10 PM

Given:

Three bells ring at intervals of 48, 60 and 90 min respectively,

Together all three bells ring at = 10 AM

Formula:

The least number which is exactly divisible by each of the given numbers is called the least common multiple of those numbers.

Calculation:

48 = 2 × 2 × 2 × 2 × 3

60 = 2 × 2 × 3 × 5

90 = 2 × 3 × 3 × 5

⇒ LCM of 48, 60 and 90 = 2 × 2 × 2 × 2 × 3 × 3 × 5 = 720 min

720 min = 720/60 = 12 hrs

∴ All three bells ring next time = 10 AM + 12 hr = 10 PM

Related Questions

In a shop, there are three clocks which chime at intervals of 15, 20 and 30 minutes respectively. They all chime together at 10 a.m. At what time will they all chime together again?
Three bells ring simultaneously at 7 p.m. They ring at regular intervals of 15 minutes, 18 minutes and 20 minutes respectively. The time when all the three bells will ring together is:
Three bells P, Q, and R are rung periodically in a school. P is rung every 20 minutes; Q is rung every 30 minutes and R is rung every 50 minutes. If all the three bells are rung at 12:00 PM, when will the three bells ring together again the next time?  
Five bells ring together and If the bells ring at intervals 5, 15, 20, 25, 30 seconds respectively, after what interval of time will they ring together again.
Three bells ring simultaneously at 10 a.m. They ring at regular intervals of 20 minutes, 30 minutes and 40 minutes respectively. The time when all the three ring together next is
3 bells ring at the time intervals of 25 minutes, 55 minutes and 45 minutes. At what time will the bells ring together?
Three bells ring simultaneously at 11 a.m. They ring at regular intervals of 20 min., 30 min., 40 min. respectively. The time when all the three bells ring together next is
Four bells toll together at 8 pm. The bells toll every 4 minutes, 6 minutes, 8minutes, and 12 minutes. At what time all the bells will ring together after 8 pm?
There are three bells which ring at regular intervals of 30, 45 and 60 seconds respectively. If all of them ring together at 1:00 PM, at what time will they ring together again?
Four bells ring at intervals of 5, 10, 12 and 15 minutes respectively. If they start ringing together at 3 o'clock, after what interval of time will they ring together and how many times will they ring together in 18 hours?