Five bells commence tolling together and toll at intervals of 2, 4, 6, 8,10 seconds respectively. In 60 minutes, how many times do they toll together?
Options:	A) 41	B) 10	C) 31	D) 16	E) 17

Rationale: l . c . m of 2 , 4,6 , 8,10 is 240 . i . e after each 2 min they will toll together . so in 60 min they will toll 30 times . as they have initially tolled once , the answer will be 30 + 1 = 31 . answer : c
Answer: C