Question

Four bells ring at intervals of 3 7 12 and 14 seconds respectively. At what time will they ring together if they start ringing at 7 a.m. full solution answer

Answer 1

LCM of 3, 7, 12, 14 = 84(2 * 2 * 3 * 7)

LCM of 3 = 3

LCM of  7 = 7 

LCm of 12 = 2*2*3 

LCM of 14 =  2*7 



So, 84 minutes = 60 + 24 

                         = 1hr 24 minutes.

                   Given 7 a.m add 1 hr 24 minutes to it, we get

                  = 8.24 AM


Hope this helps!

Answer 2

To find the answer, we need to find the LCM of 3, 7, 12, 14. 




First, list the prime factorization of each number. If you need help with prime factorization, check out this solver


3: 3 


7: 7 


12: 2*2*3 


14: 2*7 


Now highlight the unique factors. Remember, highlight the factors that occur most frequently 


3: 3 


7: 7 


12: 2*2*3 


14: 2*7 


Now multiply all of the highlighted factors 

2*2*3*7=84 

So the LCM of 3, 7, 12, and 14 is 84 


This means that every 84 minutes, the four bells will ring at the same time (you start the timer when they first ring) 


So because 84 min = 60 min + 24 min = 1 hr 24 min, add this to 07:00 to get 

07:00 + 1:24 = 08:24
this means that the four bells will ring together again at 08:24 am