The amount of a sample remaining after t days is given by the equation cap p times t is equal to cap A times 1 half raised to the t over h power , where cap A is the initial amount of the sample and h is the half-life, in days, of the substance. A scientist has a 10 -mg sample of a radioactive isotope. The isotope has a half-life of 8 days. After 16 days, how much of the radioactive isotope remains?