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?	Pick one.
A) 28 %  B) 32 %  C) 36 %  D) 40 %  E) 44 %

Rationale: the amount of chemical x in the solution is 20 + 0.25 ( 80 ) = 40 liters . 40 liters / 100 liters = 40 % the answer is d .
Answer: D