Question

six bells start ringing together and ring at interval of 4 8 10 12 15 and 20 seconds respectively.how many timeswill they ring together in 60 minutes

Answer 1

LCM of 4, 8, 10, 12, 15 and 20 = 120.
120 seconds = 2 minutes.
Hence, all the six bells will ring together in every 2 minutes.
Hence, number of times they will ring together in 60 minutes.
=1+(60/2)=31

Answer 2

Given,

Six bells, ringing interval

4,8,10,12,15,20 seconds.

To Find,

How many times do bells ring together in 60minute?

Solution,

Given that,

There are six bells.

The ringing interval of 6 bells,

4,8,10,12,15,20seconds.

Let's find the LCM of the bell ringing interval.

LCM of 4,8,10,12,15,20 = 120s.

Hence, the bells ring together =2mint.

Total number of times all the bells together =

(1+$\frac{60}{2}$) =1+30

31.

So, 31 times all the bells ring together in 60minutes.