Question 1136353
{{{y=pe^(-kx)}}}

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{{{1/2=1*e^(-k*4)}}}

{{{ln(1/2)=ln(e^(-4k))}}}

{{{-4k=ln(1/2)}}}

{{{k=(1/4)ln(2)}}}

{{{k=(1/4)0.69315}}}

{{{k=0.17329}}}

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{{{highlight_green(y=pe^(-0.17329x))}}}{{{model}}}



5 grams after 20 days:
{{{5=pe^(-0.17329*20)}}}

{{{5=p*e^(-3.4658)}}}

{{{5/0.01325=p}}}

{{{highlight(p=160)}}}{{{mg}}}