You work in a pharmacy that mixes different concentrations of saline solutions for its customers. The pharmacy has a supply of two​ concentrations, 0.50% and​ 2%. The function y=100(0.02)+x(0.005)/100+x gives the amount x in milliliters of the​ 0.5% solution you must add to 100 milliliters of the​ 2% solution to form a new concentration y of saline solution. How many milliliters of the​ 0.5% solution must you add for the combined solution to have a concentration of ​73%? You must add approximately _ mL.
(Round to one decimal place as​ needed.)