How many liters of pure alcohol must be added to a 100-liter solution that is 20 percent alcohol in order to produce a solution that is 40 percent alcohol? Choose the correct answer.
A) 7/2
B) 5
C) 100/3
D) 8
E) 39/4
20% Alcohol solution means; in the 100 liter solution, 20 liters of solution is alcohol and 80 liters other solvents.   If we addxliters of alcohol to the solution, the solution becomes100+xliters and alcohol, which was 20 liters, becomes 20+x liters.   According to the statement;   20+x = 40% of (100+x)   OR   20+x=(100+x)2/5   100+5x=200+2x   3x=100   x=100/3   Ans:100/3
<result>C</result>
How many liters of pure alcohol must be added to a 100-liter solution that is 20 percent alcohol in order to produce a solution that is 40 percent alcohol?