An unknown concentration of tap water is transferred to a 100 mL volumetric flask and diluted with DI water to 100mL. Then 50 mL of this diluted tap water is transferred to another volumetric flask and diluted again to 100mL. The absorbency is tested through experimentation with standards of Fe and fit to a calibration curve. The concentration of Fe for the twice diluted sample is found to be about 1.875ppm. What is the concentration of Fe in the original sample of tap water?