Solution X is 40% chemical A and 60% chemical B by volume. Solution Y is 50% chemical A and 50% chemical B by volume. If a mixture of X and Y is 47% chemical A, what percent of the mixture is Solution X? Pick one: A) 15 % B) 20 % C) 25 % D) 30 % E) 35 %

Rationale: "the volume of the mixture be x + y . 0.4 x + 0.5 y = 0.47 ( x + y ) x = 3 y / 7 x / ( x + y ) = ( 3 y / 7 ) / ( 10 y / 7 ) = 3 / 10 = 30 % . the answer is d ."
Answer: D