posted by Mr.Chemistry on .
A 71 mg sample of a radioactive nuclide is administered to a patient to obtain an image of her thyroid. If the nuclide has a half-life of 12 hours, how much of the nuclide remains in the patient after 4.0 days?
How many half lives is that? ANS: 8
71mg (1/2)^8= (use your calculator)