Bissoy.com
Doctors Medicines MCQs Q&A

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?

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? Correct Answer 1 hour, 18 times

Given:

Four rings well at interval respectively = 5, 10, 12, and 15

Concept:

LCM = The smallest positive number that is multiple of two or more number

Calculation:

The bell ring together again = LCM of (5, 10, 12, 15) = 60 minutes = 1 hours

⇒ The bell will ring in 18 hours = 1 × 18 = 18 times

∴ The required result will be "1 hour, 18 times".

Related Questions

Six bells start ringing simultaneously and they ring at intervals of 4, 8, 10, 12, 18 and 20 seconds respectively. Once the ringing starts, how many times will the bells ring together in next 30 minutes?
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:
Six bells start ringing together and ring at intervals of 4, 8, 10, 12, 15 and 20 seconds respectively. how many times will they ring together in 60 minutes ?
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.
Given below are quantities named A,B and C. Based on the given information, you have to determine the relation between the quantities. You should use the given data and your knowledge of mathematics to choose among the possible answer. Quantity A: Tap1 and Tap2 can fill the tank in 16 hours and 25 hours respectively. Both the taps opened together. After some time Tap 1 is closed and after that the tank is filled in 12 hours. In how many hour Tap 1 and 2 work together? Quantity B: Three taps 1, 2, 3 can fill a cistern in 10,14,18 hours respectively. If tap 1 is kept open all the time and tap 2 and 3 is opened alternatively for an hour then find in how many hours the tank will be filled? Quantity C: Two taps 1 and 2 are such that tap 1 fills the tank in 10 hours and tap2 empties it in 20 hours. If tap 1 is opened first and after 5 hours tap 1 is closed and tap 2 is opened, then the tank emptied in x hours and find the value of x?
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?
Four bells ringing together and ring at an interval of 12 sec, 15 sec, 20 sec, and 30 sec respectively. How many times will they ring together in 8 hours?  
3 bells ring at the time intervals of 25 minutes, 55 minutes and 45 minutes. At what time will the bells ring together?
Six bells starts ringing logether and ring at intervals of 4, 8, 10, 12, 15 and 20 seconds respectively. How many times will they ring together in 60 minutes?
5 bells ring simultaneously at intervals of 4, 5, 8, 9 and 10 seconds. All the bells start ringing simultaneously. When will they play together next time: