i have no idea if im doing this correct
400 = (1 - e^-.2t
ln400 = -.2tln(500(1- e)
.2t = ln(500(1 - e)
ln(400)
im stuck here, any help would be great
im trying to solve for T which indicates times in the problem
$\displaystyle 1 - e^{-.2t} = \frac{400}{500}$
$\displaystyle 1 = \frac{400}{500} + e^{-.2t}$
$\displaystyle 1 = \frac{4}{5} + e^{-.2t}$
$\displaystyle 1 - \frac{4}{5} = e^{-.2t}$
$\displaystyle \frac{1}{5} = e^{-.2t}$
$\displaystyle 0.2 = e^{-.2t}$