document.write( "Question 893940: A radioactive isotope has a half-life of 14 hours. Find the amount of the isotope left from a 320-milligram sample after 42 hours. If necessary, round your answer to the nearest thousandth.
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Algebra.Com's Answer #541641 by Alan3354(69443)\"\" \"About 
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A radioactive isotope has a half-life of 14 hours. Find the amount of the isotope left from a 320-milligram sample after 42 hours. If necessary, round your answer to the nearest thousandth.
\n" ); document.write( "42 = 3*14, 3 half-lives
\n" ); document.write( "--> 320*(1/2)*(1/2)*(1/2)
\n" ); document.write( "= 40 mg
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