# In 30 Minutes How Many Times do They Toll Together?

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

- 4
- 10
- 15
- 16

**Answer: (4) 16.
Explanation:-**

The LCM of 2, 4, 6, 8, 10, 12 is 120

Therefore, the bells toll after every 120 sec.

120 sec = 120/60 = 2 min.

In 30 minutes, they will toll together = 30 /2 + 1 = 15 + 1 = 16

Hence, the answer is (4) 16.