Question 185081
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You have done everything right.  It is just that when you got to the point of saying:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  \frac{1}{16} = \left(\frac{1}{2}\right)^{\frac{x}{25}}]


You might have noticed that:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \  \frac{1}{16} = \left(\frac{1}{2}\right)^4]


From which you could then deduce that:


*[tex \LARGE \ \ \ \ \ \ \ \ \ \ \frac{x}{25} = 4]


I think you should be able to take it from there.


The answer you got by using logs <i><b>would</b></i> have been correct if you had not, for some inexplicable reason, changed the half-life number from 25 to 5 in the denominator of your fractional exponent.


John
*[tex \LARGE e^{i\pi} + 1 = 0]
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