Question

Six bells commence tolling together and toll at interval of 2,4,6,8,10,12 minutes respectively.In 30 hours,how many times do thry toll together

Answer 1

n = 15
Hope you understand my answer and writing

120 divides all time intervals .
At every 120th minute all bells toll together
No. of times all toll together is 30* 60/120 = 15

Sorry , initially I mistaken the question , so given wrong approach .
But , now I think answer is suitable to your question.