Question 977781
{{{highlight_green(y=p*e^(-kx))}}}


{{{1/2=1*e^(-k*5770)}}}
{{{ln(1/2)=-k*5770}}}
{{{ln(1/2)/5770=-k}}}
{{{k=-ln(1/2)/5770}}}
{{{highlight_green(k=1.201*10^(-4))}}}



(a):
{{{0.25=1*e^(-1.201*10^(-4)*x)}}}
{{{ln(0.25)=-1.201*10^(-4)*x}}}
{{{x=ln(0.25)/(-1.201*10^(-4))}}}
{{{highlight(x=11540)}}}


(b):
{{{ln(y)=ln(p)+(-k*t)}}}
{{{ln(y)-ln(p)=-k*t}}}
{{{kt=ln(p)-ln(y)}}}
{{{highlight_green(t=(ln(p)-ln(y))/k)}}}