A solution containing Cu(II) is analyzed for copper by transferring exactly 5.00 mL into an absorption cell with a 1.00 cm pathlength. The measured % transmittance at the maximum wavelength is 75.3%. A 1.000 mL portion of 0.01000 Cu(II) is then added to the same cell and mixed with the original solution, resulting in a new transmittance of 62.5%. What is the concentration of Cu(II) in the original solution in mg/L?