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 equals StartFraction 100 left parenthesis 0.02 right parenthesis plus x left parenthesis 0.005 right parenthesis Over 100 plus x EndFraction 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 0.87%