Calculate the L.C.M of 7/10, 8/ 9, 3/8, 5/12 is :  Choose the correct choice from the following choices.
A) 840  B) 70  C) 740  D) 140  E) 940

Rationale: required l . c . m = l . c . m . of 7 , 8 , 3 , 5 / h . c . f . of 10 , 9 , 8 , 12 = 840 / 1 = 840 answer is a
Answer: A