In two volumetric flasks with a capacity of 100.0 ml were placed 10 ml of wastewater. In one flask, 10.00 ml of a standard copper sulphate solution with a copper titer of 0.0010 g / ml was added. In both flasks introduced solutions of ammonia, ruba nitric acid and diluted with water until the label. Photometry of the solutions yields optical densities of AX = 0.240 and Ax + a = 0.38. Determine the concentration (g / l) of copper in the waste water.