List of top Quantitative Aptitude Questions on Mixtures and Allegations asked in BHU PET

A 90 kg solution has 10% salt. How much water must be evaporated to have the solution with 20% salt?
In 35 litre mixture, ratio of milk and water is 4 : 1. If 7 litre more water is added to the mixture, then the new ratio of milk and water will be:
How many liters of water will have to be added to 1125 liters of 45% solution of acid so that the resulting mixture will contain more than 25% but less than 30% acid content?