While cleaning the organic stockroom, a student found a bottle of ethanol labeled "Denatured with Benzene." He decided to determine the concentration of benzene in the ethanol by acquiring the UV spectrum of the liquid in a 2.0 cm cell. The spectrum exhibited an absorption band at 260 nm which is attrbutable to benzene, and the absorbance of this band was 0.69. In a reference source, the student found that the molar absorptivity of this benzene band in ethanol was 230 M-1cm-1. Show how the student calculated the concentration of the benzene in the ethanol.