Question

Six bells commence tolling together and toll at intervals of 2,4,7,8,10,12 sec respectively...in 30 min how many times do they toll together

Answer 1

To find the time when they will toll together after initial toll , take the LCM of the intervals .

LCM of (2,4,7,8,10,12) = 840

i.e. The bells will toll together after 840sec = 14 min .

So in 30 mins the no. of time they toll together = 30/14

The no. of time they toll together in 30 mins = 2 .

After 14 min and 28 min .

Hope u get tis easily , for doubt comment .