The average weight of 6 person's increases by 3.5 kg when a new person comes in place of one of them weighing 47 kg. What might be the weight of the new person?  Choose the correct choice from the following.
A) 60 kg B) 75 kg C) 68 kg D) 85 kg E) 90 kg

Rationale: "total weight increased = ( 6 x 3.5 ) kg = 21 kg . weight of new person = ( 47 + 21 ) kg = 68 kg option c"
Answer: C