There are two vessels A and B containing 35 litres each of pure milk and pure water respectively .5 litres of milk from A is taken and poured into B, then 8 litre of mixture from B is taken and poured into A .What is the ratio of water in A and B respectively:

This is a step-by-step mixture transfer problem. Initially: A has 35L milk, B has 35L water. Step 1: Transfer 5L milk from A to B. A now has 30L milk, B has 35L water + 5L milk = 40L mixture with 5/40 = 1/8 milk concentration. Step 2: Transfer 8L from B to A. This 8L contains 8 × 1/8 = 1L milk and 7L water. A now has 30L + 1L = 31L milk and 7L water. B now has 40L - 8L = 32L remaining, with 5L - 1L = 4L milk and 35L - 7L = 28L water. Water ratio (A:B) = 7:28 = 1:4. Option C is correct.