A big container is 30% full with water. If 9 liters of water is added, the container becomes 3/4 full. What is the capacity of the big container? Choices
A) 20 liters B) 40 liters C) 45 liters D) 54 liters E) 60 liters

Rationale: "a big container is 30 % full with water and after 9 liters of water is added , the container becomes 75 % full . hence these 9 liters account for 45 % of the container , which means that the capacity of it is 9 / 0.45 = 20 liters . or : if the capacity of the container is x liters then : 0.3 x + 9 = 0.75 x - - > x = 20 liters . answer : a ."
Answer: A