Five bells commence tolling together and toll at intervals of 2, 4, 6, 8 10 seconds respectively. In 20 minutes, how many times do they toll together?
Pick one:
A) 11  B) 10  C) 15  D) 16  E) 17
L.C.M of 2,4,6,8,10 is 240. i.e after each 2 min they will toll together.So in 20 min they will toll 10 times.As they have initially tolled once,The answer will be  10+1= 
<gadget id="calculator"> 10+1</gadget>
<output>11</output>
11.   11NSWER:11
<result>A</result>
Five bells commence tolling together and toll at intervals of 2, 4, 6, 8 10 seconds respectively. In 20 minutes, how many times do they toll together?