Question 998881
Let n be the amount needed to be extracted from the solution. Since the solution is 65% alcohol, out of 1000 liters of solution, this gives us 650 liters of pure alcohol. So:
650-n=.5(1000-n)
650-n=500-.5n
.5n=150
n=300
300 liters of alcohol must be extracted to get a solution of 700 liters of 50% solution. ☺☺☺☺