# How many Times They will Toll Together in one Hour?

Five bells begin to toll together and toll respectively at intervals of 6, 7, 8, 9 and 12 seconds. How many times they will toll together in one hour?

- 5
- 14
- 6
- 7

**Answer: (4) 7 **

**Explanation:-
**The LCM of 6, 7, 8, 9 and 12 = 2 x 2 x 2 x 3 x 3 x 7

= 504

Then, the toll together 504 sec after.

1 hour = 60 min

1 min = 60 sec

Therefore,

60 min = 60 x 60 sec

Then, 1 hour = 3600 sec

The number of toll in one hour = 3600/504

= 7 time and 72 sec remaining

Then, 7 times tool in one hour.

Hence, the answer is (4) 7.