document.write( "Question 1162581: The half-life of a radioactive material is about 34.3 years. How much of a 1-gram sample of the material is left after 20 years? (Round your answer to four decimal places.) \n" ); document.write( "

Algebra.Com's Answer #786399 by greenestamps(13216) $\"\"$ $\"About$

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\n" ); document.write( "The amount remaining, y, of an initial amount x, is
\n" ); document.write( " $\"y+=+x%28%281%2F2%29%5En%29\"$

\n" ); document.write( "where n is the number of half lives.

\n" ); document.write( "The number of half lives is the number of years, divided by the number of years in a half life.

\n" ); document.write( "We are given x=1g and we are to find y:

\n" ); document.write( " $\"y+=+1%28%281%2F2%29%5E%2820%2F34.3%29%29\"$

\n" ); document.write( "Use a calculator....

\n" ); document.write( "Very roughly, 20 years is something less than a half life, so your calculation should show an answer of slightly more than 0.5g remaining. If you get a much different answer, you aren't doing the calculation correctly.

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