Mixture P consists of lime juice and water, containing 45% lime juice and the remaining water. If x ml of lime juice and 2x ml of water are added to mixture P, the ratio of lime juice to water in the resultant mixture becomes 15:23. Find the ratio of the initial quantity of mixture P to x.

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?