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 ? Choose the correct answer
A) 4  B) 10  C) 15  D) 16  E) 17
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= 
<gadget id="calculator"> 30/2+ 1</gadget>
<output>16</output>
16 times.   ANSWER IS 16
<result>D</result>
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 ?