Naturally occurring cobalt consists of only one isotope, 59-Co, whose relative atomic mass is 58.9332. A synthetic radioactive isotope of cobalt, 60-Co, relative atomic mass 59.9338, is used in radiation therapy for cancer. A 1.8330 g sample of cobalt has an apparent "atomic mass" of 58.9901. Find the mass of 60-Co in this sample. Express your answer with the appropriate units.