A clinical researcher prepares a dose of a radioactive tracer containing 160 μg160\text{ }\mu\text{g}160 μg of a specific isotope for a diagnostic scan. The isotope has a half-life of 8.0 days8.0\text{ days}8.0 days.
Calculate the mass of this isotope remaining in the sample after 40 days40\text{ days}40 days.