The average weight of 9 persons increases by 1.5 kg. If a person weighing 65 kg is replaced by a new person, what could be the weight of the new person?
Choose the correct answer:
A) 76 kg
B) 77 kg
C) 78.5 kg
D) data inadequate
E) none of these

Rationale: "total weight increases = 9 × 1.5 = 13.5 kg so the weight of new person = 65 + 13.5 = 78.5 kg answer c"
Answer: C