Total quantity of solution containing alcohol and water = 60 liters Amount of alcohol in the solution = 20 liters Percentage of alcohol in the solution = (20/60) * 100 = 100/3 = 33.33 percent So 33.33 percent alcohol is = 20 liters Then 50 percent alcohol = [20/(100/3)] * 50 = [(20 * 3)/100] * 50 = (60 * 50)/100 = 3000/100 = 30 liters So 30 liters of alcohol should be added to make the percentage of alcohol 50% in the solution.
