Mixtures Alligations

A shopkeeper purchases 40 kg of rice at the rate of per kg and kg of rice at the rate of per kg. If he sells the mixture to make a profit of , the corresponding selling price for this transaction is:

10 litres of concentrated acid containing 75% of acid and rest water is mixed with X litres of diluted acid containing 40% of acid and rest water. If the final mixture contains 60% of acid then value of X is: