A 6-liter solution is 20% alcohol. How many liters of pure alcohol must be added to produce a solution that is 50% alcohol? Choose the correct choice from the following answers:
A) 2.4
B) 2.7
C) 3.0
D) 3.3
E) 3.6

Rationale: "let x be the amount of pure alcohol required . 0.2 ( 6 ) + x = 0.5 ( x + 6 ) 0.5 x = 3 - 1.2 x = 3.6 liters the answer is e ."
Answer: E