The smallest fraction, which each of 6/7, 5/14, 10/21 will divide exactly is: Choose one.
A) 30 / 7
B) 30 / 98
C) 60 / 147
D) 50 / 294
E) 52 / 294

Rationale: required fraction = l . c . m of 6 / 7 , 5 / 14 , 10 / 21 = ( l . c . m of 6 , 5 , 10 ) / ( h . c . f of 7 , 14 , 21 ) = 30 / 7 answer : a
Answer: A