Question 1162581
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Since the input data is given in half-lives, the simplest way to solve the problem is to make all calculations base 2.


<pre>
The remaining mass formula is  {{{M[remaining]}}} = {{{M[start]*(1/2)^(t/34.3)}}},  where t is the time in years.


Substituting t= 20 years, you have  {{{20/34.3}}} = 0.5831 half-life times;  therefore


    {{{M[remaining]}}} = {{{1/2^0.5831}}} = 0.6675  grams.
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Solved.


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See the lesson

&nbsp;&nbsp;&nbsp;&nbsp;- <A HREF=https://www.algebra.com/algebra/homework/logarithm/Radioactive-decay-problems.lesson>Radioactive decay problems</A> 

in this site.



The subject to learn from my post is THIS:


<pre>
    If input data is given in terms of half-life, the problem can be solved in these terms to the end with minimum efforts/calculations.


    It is NOT NECESSARY to convert data to ekt-model - on contrary, it is excessive and non-necessary work in this case.
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