Three vessels A , B and C of the same capacity are all full. Vessels  A and B contain mixture  of milk and water in ratio 4 : 1 and 7 : 3 while vessel C contains only pure milk. The contents of all the vessels are poured into a larger vessel D. After drawing 30 lt of the mixture from vessel D, the final quantity of water in vessel D is 40 lt.  Find the capacity of each vessel.