a milkman purchases the milk at rs. x per litre and sells it at rs. 2x per litre still he mixes 2 litres water with every 6 litres of pure milk. what is the profit percentage?

It looks like your question got cut off. From what you’ve written, here’s what I understand so far:

• A milkman purchases milk at Rs. x per litre.
• He sells the milk at Rs. 2x per litre.
• He mixes 2 litres of water with every ... (the quantity is missing).

Could you please provide the rest of the question? For example, how many litres of milk he mixes the 2 litres of water with, or what exactly you want to find (profit percentage, cost price, selling price, etc.)? Once you provide the full details, I can help you solve the problem step-by-step!