Iridium-192 has a half-life of 74 days. What fraction of a sample of this isotope will remain after 222 days?

Name: Iridium-192 has a half-life of 74 days. What fraction of a sample of this isotope will remain after 222 days?
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Question

Quizplus · Accepted Answer

After 74 days, half of the original sample will remain. After another 74 days, half of that remaining half will remain, or 1/4 of the original sample. After a total of 222 days (three half-lives), only 1/8 of the original sample will remain. Therefore, the answer is D) 1/8.

Iridium-192 Has a Half-Life of 74 Days