Question 143983
Given {{{N = P (1 - e^(-0.15d)) }}}  P=1000, N = 500
{{{500 = 1000 (1 - e^(-0.15d)) }}} 
{{{0.5= (1 - e^(-0.15d)) }}} 
{{{-0.5= - e^(-0.15d) }}} 
{{{0.5=  e^(-0.15d) }}} 
{{{ln(0.5) = -0.15d}}}
{{{-0.69314 = -0.15d}}}
{{{4.62 = d }}}