A milkman purchases milk at ₹'a' per litre and sells it at ₹.5a per litre. Still he mixes 2 litres water with every 9 litres of pure milk. What is his profit percentage?
\( \frac{250}{3}\% \)
\( \frac{328}{9}\% \)
\( \frac{789}{5}\% \)
\( \frac{1000}{3}\% \)
Visitors to a show were charged ₹10 each on the first day, ₹5 on the second day and ₹2 on the third day and the total attendance on the three days was in the ratio 15 : 2 : 3. What is the average charge per person for the visitors to the show on the three days taken together?