Question 601067
{{{A(t) = A[0]e^(rt)}}}


{{{50 = 100*e^(-0.00023t)}}}


{{{50/100 = e^(-0.00023t)}}}


{{{0.5 = e^(-0.00023t)}}}


{{{ln(0.5) = ln(e^(-0.00023t))}}}


{{{ln(0.5) = -0.00023t*ln(e)}}}


{{{ln(0.5) = -0.00023t*(1)}}}


{{{ln(0.5) = -0.00023t}}}


{{{ln(0.5)/-0.00023 = t}}}


{{{-0.693147180559945/-0.00023 = t}}}


{{{3013.68339373889 = t}}}


{{{t = 3013.68339373889}}}



So the half-life is roughly 3013.68339 years.