Question 1029433
Is this it?
{{{ p = m / ( 1 + e^(-k*t ) ) }}}
If so,
{{{ p*( 1 + e^(-k*t ) ) = m }}}
{{{ 1 + e^(-k*t ) = m/p }}}
{{{ e^(-k*t) = m/p - 1 }}}
Take the natural log of both sides
{{{ -k*t = ln( m/p - 1 ) }}}
{{{ t = (-1/k)*ln( m/p - 1 ) }}}