A chemist mixes one liter of pure water with x liters of a 75% salt solution, and the resulting mixture is a 15% salt solution. What is the value of x? Select.
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 = 75 % concentration of salt in the mixed solution = 15 % the pure solution and the salt solution is mixed in the ratio of - - > ( 75 - 15 ) / ( 15 - 0 ) = 4 / 1 1 / x = 4 / 1 x = 1 / 4 answer : a"
Answer: A