document.write( "Question 1201597: Radioactive Carbon-14,which is found in all living things, has a half-life of 5700 years and can be used to date fossils. Suppose a fossil contains 15% of the amount of Carbon-14 that the organism contained when it was alive. Calculate the age of the fossil. \n" ); document.write( "
Algebra.Com's Answer #836051 by Theo(13342)\"\" \"About 
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the half life is 5700.
\n" ); document.write( "equation for that is 1/2 = (1 + r) ^ 5700
\n" ); document.write( "solve for (1 + r) to get (1 + r) = (1/2) ^ (1/5700) = .9998784026.
\n" ); document.write( "that's the growth factor per year.
\n" ); document.write( "in 5700 years, a present value of 1 is equal to .9998784026 ^ 5700 = .5
\n" ); document.write( "if a fossil contains 15% of the carbon-14 that it contained when it was alive, the formmula becomes:
\n" ); document.write( ".15 = .9998784026 ^ x
\n" ); document.write( "take the log of both sides of the equation to get:
\n" ); document.write( "log(.15) = log(.9998784016 ^ x)
\n" ); document.write( "this becomes log(.15) = x * log(.9998784026)
\n" ); document.write( "solve for x to get x = log(.15) / log(.9998784026) = 15600.70389.
\n" ); document.write( "the age of the fossil is 15600.70389 years.
\n" ); document.write( "the equation can be graphed as y = .9998784026 ^ x, as shown below.
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