If 20 liters of chemical X are added to 80 liters of a mixture that is 25% chemical X and 75% chemical Y, then what percentage of the resulting mixture is chemical X?  Choose the correct choice from the following:
A) 28%
B) 32%
C) 36%
D) 40%
E) 44%
The amount of chemical X in the solution is 20 +0.25(80) = 40 liters.   40 liters / 100 liters = 40%   The answer is 40%.
<result>D</result>
If 20 liters of chemical X are added to 80 liters of a mixture that is 25% chemical X and 75% chemical Y, then what percentage of the resulting mixture is chemical X?