Question

3 bells commence tolling together and toll at intervals of 8, 10 and 12 seconds respectively. The bells will toll together after every

• A. 110
• B. 100
• C. 120

Answer 1

The correct option is C 120

The given numbers are 8,10 and 12.
The factors of the given numbers are:
8=2$\times$2$\times$2
10=2$\times$5
12=2$\times$2$\times$3
Now ,the maximum number of times prime factor 2 occurs is 3,
the maximum number of times prime factor 3 occurs is 1,
the maximum number of times prime factor 5 occurs is 1.
So, LCM=2$\times$2$\times$2$\times$3$\times$5 = 120
L.C.M. of 8, 10 and 12 is 120.
So, the bells will toll together after every 120 seconds (2 minutes).