₹38 प्रति किग्रा लागत वाली चीनी को ₹55 प्रति किग्रा लागत वाली चीनी के साथ किस अनुपात में मिलाया जाना चाहिए ताकि मिश्रण को ₹57.20 प्रति किग्रा पर बेचने पर 10% का लाभ हो?

A vessel has 20 litres of milk. From this vessel, 5 litres of milk is taken out and replaced by water. The process is repeated once more. Find the quantity of milk (in litres) remaining in the vessel.

A shopkeeper mixes 40 kg of rice costing ₹30/kg with 60 kg of rice costing ₹50/kg. What is the average price (in ₹/kg) of the mixture?