An assistant in a dental office just found 9 liters of 3% fluoride solution. The lab also routinely stocks a large quantity of 13% fluoride solution. How much of the 13% solution should be mixed with the 9 liters of 3% fluoride solution to make a 4% fluoride solution? Write your answer as a whole number or as a decimal rounded to the nearest tenth. liters Submit Work it out Not feeling ready yet? These can help: percent word problems nates please explain