Suppose That One Solution Contains 20% Alcohol and Another Solution

Multiple Choice

Suppose that one solution contains 20% alcohol and another solution contains 50% alcohol. How many liters of each solution should be mixed to make 12 liters of a 40%-alcohol solution?

A) 6 liters of 20% solution and 6 liters of 50% solution
B) 4 liters of 20% solution and 8 liters of 50% solution
C) 8 liters of 20% solution and 4 liters of 50% solution