CMAT 2025 Alligations and Mixtures — Previous Year Question

Three vessels P, Q and R of the same capacity are all full. Vessels P and Q contain a mixture of milk and water in the ratios 4:1 and 7:3 respectively, while vessel R contains only pure milk. The contents of these vessels are poured into a larger vessel S. After drawing 30 litres of mixture from vessel S, the final quantity of water left in vessel S is 40 litres. Then the capacity of each vessel is: