document.write( "Question 688703: Radioactive strontium-90 is used in nuclear reactors and decays according to A=Pe^-0.0248t where A is the amount remaining after t years. Find the time required for strontium-90 to decay to 1/10 of the quantity present now?
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Algebra.Com's Answer #425712 by ankor@dixie-net.com(22740) $\"\"$ $\"About$

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Radioactive strontium-90 is used in nuclear reactors and decays according to A=Pe^-0.0248t
\n" ); document.write( " where A is the amount remaining after t years.
\n" ); document.write( " Find the time required for strontium-90 to decay to 1/10 of the quantity present now?
\n" ); document.write( ":
\n" ); document.write( "Let the initial amt (P) = 1; A = .1
\n" ); document.write( " $\"1%2Ae%5E%28-.0248t%29+=+.1\"$
\n" ); document.write( "natural log of e = 1, therefore we can write it
\n" ); document.write( "-.0248t = ln(.1)
\n" ); document.write( "t = $\"ln%28.1%29%2F%28-.0248%29\"$ ; use a calc
\n" ); document.write( "t ~ 93 years \n" ); document.write( "

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