The change in the optimal quantity of a good when its price changes and the consumer’s income is adjusted so that she can just buy the bundle that she was buying before the price change is called?
A mixture contains acid and water in the ratio of 7 : 3. If 4 litres of water is added to it, then the ratio of acid and water becomes 7 : 4. What is the quantity (in litres) of acid in the mixture?