Question 903876
{{{Q=q*e^(kt)}}} using q=2500, and I am using two variables differently than are you.


Your half-life information goes this way:
t for half life is t=5.
Q=(1/2)q, so form a more specific equation as:
{{{1/2=1*e^(k*5)}}}
{{{ln(1/2)=ln(e^(5k))}}}
{{{5k*1=ln(1/2)}}}
{{{k=(1/5)ln(1/2)}}}
{{{highlight(k=-(1/5)ln(2))}}}, for a decimal value of approximately {{{-0.139}}}.



Model to use, {{{highlight(Q=2500*e^(-0.139*t))}}}.