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A 0.500-g sample is analyzed spectrophotometrically for manganese by dissolving it in acid and transferring to a 250-mL flask and diluting to volume. Three aliquosts are analyzed by transferring 50-mL portions with a pipet to 500-mL Erirnmeyer flasks and reacting with an oxidizing agent, potasium peroxydisulfate, to convert the manganese to permanaganate. After reaction, they are quantitatively trnasferred to 250-mL volumetric flasks, diluted to volume, and measured spectrophotometrically. By comparison to standards, the average concentration in the final solution is determined to be 1.25 x 10^-5 M. What is the percent of manganese in the sample?