A mixture contains liquid A and liquid B in the ratio of 5 : 4. If 2 litres of liquid B is added to it, then the ratio of liquid A and liquid B becomes 7 : 6. What is the quantity (in litres) of liquid A in the mixture?
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?