Discussion Forum



1)

Six bells commence tolling together and toll at intervals of 2, 4, 6, 8, 10 and 12 seconds respectively. In 30 minutes, how many times do they toll together ?


A) 4

B) 10

C) 15

D) 16

Answer:

Option D

Explanation:

L.C.M. of 2, 4, 6, 8, 10, 12 is 120.
So, the bells will toll together after every 120 seconds(2 minutes).
In 30 minutes, they will toll together (30/2)+ 1 = 16 times.
Since the bells start tolling together, the first toll also needs to be counted. Therefore we need to add 1.