A chemist mixes one liter of pure water with x liters of a 30% salt solution, and the resulting mixture is a 15% salt solution. What is the value of x?
Pick one.
A) 1 / 4	B) 1 / 3	C) 1 / 2	D) 1	E) 3

Rationale: "concentration of salt in pure solution = 0 concentration of salt in salt solution = 30 % concentration of salt in the mixed solution = 15 % the pure solution and the salt solution is mixed in the ratio of - - > ( 30 - 15 ) / ( 15 - 0 ) = 1 / 1 1 / x = 1 / 1 x = 1 answer : d"
Answer: D