What is the average number of students appearing for the Aptitude Test from all the towns together?

Answer: Option A

Average number of students appearing in Aptitude Test from all towns
  $$=\frac{\left(40+32.5+17.5+42.5+35\right)\times 1000}{5}$$
$$\begin{array}{rl}& =\frac{167.5\times 1000}{5}\\ & =33.5\times 1000\\ & =33500\end{array}$$