A drunker have a 27 litres of a bottle of wine. He removed one third of the wine and then added equal amount of water. Again he replaced one third of the mixture by water. Find the respective ratio of the wine and the water in the final mixture.

Starting: 27 litres wine, 0 litres water. After first replacement: remove 1/3 of 27 = 9 litres wine, add 9 litres water → 18 wine, 9 water. After second replacement: remove 1/3 of 27 = 9 litres of mixture (proportionally 6 wine, 3 water) → 12 wine, 6 water, then add 9 litres water → 12 wine, 15 water. Ratio = 12:15 = 4:5.