Solution X is 10% chemical A and 90% chemical B by volume. Solution Y is 20% chemical A and 80% chemical B by volume. If a mixture of X and Y is 12% chemical A, what percent of the mixture is Solution X?
Pick one
A) 80 % B) 75 % C) 70 % D) 65 % E) 60 %

Rationale: "the volume of the mixture be x + y . 0.1 x + 0.2 y = 0.12 ( x + y ) x = 4 y x / ( x + y ) = 4 / 5 = 80 % . the answer is a ."
Answer: A