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Doctors can use radioactive iodine to treat some forms of cancer. The half-life of iodine - 131 is 8 days. A patient receives a treatment of 12 millicuries of iodine - 131. (A mullicurie is a unit of radioactivity.) How much iodine - 131 remains in the patient 16 days later?

1 answer

amount = 12 (1/2)^(168)
= 12(1/2)^2 = 3 millicuries