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Homework Help: Simple log problem

  1. Dec 23, 2005 #1
    If 3150g of a radioactive substance decays to 450g in 73 weeks, determine the half life of the substance to the nearest week. Solve algebraically using logarithms.

    450=3150(x)^73
    450/3150=x^73
    73sqrt(450/3150)=x

    Now, the only problem is the answer says it is 26 weeks. Any help is much appreciated.
     
  2. jcsd
  3. Dec 23, 2005 #2

    Tide

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    Homework Helper

    You're starting with the wrong equation. Try something like

    [tex]450 = 3150 \left( \frac {1}{2} \right)^{73/T}[/tex]

    where T is the half-life.
     
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