a 1.509g sample of P/Cd alloy was dissolved in acid and diluted to exactly 250ml in a volumetric flask. a 50ml aliquot of distilled solution was brought to a pH of 10 with NH4/NH3 buffer; the subsequent titration involve both cations and required 28.89 ml of .06950M EDTA. A second 50ml aliquot was brought to a pH of 10 with an HCN/NaCN buffer, which also served to mask Cd2+; 11.56 ml of EDTA solution were needed to titrate the Pb2+. Calculate the percentage of Pb and Cd in the sample.