The capacities of three containers P, Q and R are in the proportion of 5 ∶ 4 ∶ 8. They are completely filled with a mixture of milk and water in the proportions of 1 ∶ 4, 2 ∶ 3 and 3 ∶ 5, respectively. If the mixtures of all the three containers are mixed together, then what will be the proportion of milk to water in the final mixture?