document.write( "Question 1156567: A tumor is injected with 0.6 grams of Iodine-125, which has a decay rate of 1.15% per day. To the nearest day, how long will it take for half of the Iodine-125 to decay? \n" ); document.write( "

Algebra.Com's Answer #779288 by ikleyn(52833) $\"\"$ $\"About$

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document.write( "The decay equation in this case is\r\n" );
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document.write( "    M =  = ,\r\n" );
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document.write( "where  is the original mass, M is the current mass, t is the time in days.\r\n" );
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document.write( "They want you find \"t\"  from the condition  M = .\r\n" );
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document.write( "It gives\r\n" );
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document.write( "    0.5 = .\r\n" );
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document.write( "Take the logarithm base 10 from both sides\r\n" );
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document.write( "    log(0.5) = t*log(0.9885).\r\n" );
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document.write( "Hence,  t =  = 59.93 = 60 days  (rounded as required).    ANSWER\r\n" );
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