document.write( "Question 1126133: Radioactive Decay. Strontium-90 has a half-life of 28 years. How long will it take for 40 grams of this to decay to 5 grams? Apply the formula N= N0e^rt, where N is the number of grams.\r
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Algebra.Com's Answer #742491 by ikleyn(52824) $\"\"$ $\"About$

You can put this solution on YOUR website!
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document.write( "The ratio  of 5 grams to 40 grams is   = , which is  (fortunately !) exactly  .\r\n" );
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document.write( "It means that 40 grams will decay to 5 grams in the time which is exactly thrice the half-period, or exactly in 3*28 = 84 years.\r\n" );
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\n" ); document.write( "\n" ); document.write( "The instruction placed at the end of your post is VERY BAD advise on how to solve the given problem.\r
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\n" ); document.write( "\n" ); document.write( "The much simpler way is that I showed in my post.\r
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