Question : A 40-litre mixture of milk and water contains milk and water in the ratio of 7 : 3. How many litres of water should be added to the mixture so that the resulting mixture has 60% water in it?

Question : A mixture contains liquid A and B in the ratio 5 : 3, respectively. If 3 litres of liquid B is added to it, the ratio of liquid A to liquid B becomes 7 : 6. What is the quantity of liquid A in the mixture?

Question : A bottle is filled with liquid, of which 4 parts are water and 5 parts are fruit extract. How much of the mixture must be drawn off and replaced with water so that the mixture may be half water and half fruit extract?

Question : A mixture of 70 litres of wine and water contains 10% of water. How much water must be added to make the water $12 \frac{1}{2}\%$ of the resulting mixture?

Question : In a mixture of 178 litres, the ratio of water and milk is 5 : 7. How much water should be added to make the ratio of water and milk 3 : 4?