document.write( "Question 1072846: The half-¬life of a radioactive substance is the time it takes for half of the atoms of the substance to disintegrate. All life on Earth contains Carbon¬14, which decays continuously at a fixed rate. The half-¬life of Carbon-14 is 5760 years. That is, every 5760 years half of a mass of Carbon-14 decays away. If a specimen that originally contained 150 milligrams of Carbon¬14 now contains 130 milligrams, how old is the fossil? \n" ); document.write( "

Algebra.Com's Answer #687708 by Fombitz(32388) $\"\"$ $\"About$

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$\"N=N%5B0%5D%281%2F2%29%5E%28t%2F5760%29\"$
\n" ); document.write( " $\"130=150%281%2F2%29%5E%28t%2F5760%29\"$
\n" ); document.write( " $\"130%2F150=%281%2F2%29%5E%28t%2F5760%29\"$
\n" ); document.write( " $\"ln%28130%2F150%29%2Fln%281%2F2%29=t%2F5760\"$
\n" ); document.write( " $\"t=5760%2A%28ln%28130%2F150%29%2Fln%281%2F2%29%29\"$
\n" ); document.write( "or approximately,
\n" ); document.write( " $\"t=1189\"$ $\"years\"$
\n" ); document.write( " \n" ); document.write( "

\n" );