A mixture of 40 liters of milk and water contains 10% water. How much water should be added to make it 20% in the new mixture?

प्रारंभिक पानी = 40 का 10% = 4L। दूध = 36L। नए मिश्रण में, दूध (36L) 80% है। तो 80% = 36 => 100% = (36/80)*100 = 45L। नए मिश्रण का आयतन = 45L। मिलाया गया पानी = 45 - 40 = 5 लीटर।