Alligation or Mixture problems
From a vessel filled with alcohol 1/5 of its contents is removed and the vessel is then filled up with water. If this be done 5 times in succession, what proportion of the alcohol originally contained in the vessel will have been removed from it?
Number of liters of water in 150 liters of the mixture = 20% of 150 = 20/100 x 150 = 30 liters.P liters of water added to the mixture to make water 25% of the new mixture.Total amount of water becomes (30 + P) and total volume of mixture is (150 + P).(30 + P) = 25/100 x (150 + P)120 + 4P = 150 + P => P = 10 liters.