The average weight of 8 person's increases by 2.5 kg when a new person comes in place of one of them weighing 65 kg. What is the weight of the new person?
Answer: C
Total increase in weight \(= 8 \times 2.5 = 20\)
If \(x\) is the weight of the new person, total increase in weight \(= x-65\)
\(\Rightarrow 20 = x - 65\\
\Rightarrow x = 20 + 65 = 85\)