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A 24-gram sample of a radioactive nuclide decayed to 3.0 grams of the nuclide in 36 minutes. How much of the original nuclide sample remained after the first 12 minutes?

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bartdrinksmalk

The sample decreased to \(\frac{1}{8}\) of its original size, so it underwent \(\log_{2} 8=3\) half-lives.

One half life is then
\(\frac{36\ min}{3}=12\ min\)

One-half of 24 grams is 12 grams, so 12 grams remained after the first 12 minutes.