We don't normally post solutions, but will help you to get the solution. You have divided through by 2,70, and so you have:
$\displaystyle \frac{1,5}{2,70}=1-e^{-0,021t}$
I would simplify the left by observing:
$\displaystyle \frac{1,5}{2,70}=\frac{15}{27}=\frac{5}{9}$ and so we have:
$\displaystyle \frac{5}{9}=1-e^{-0,021t}$
What do you think is a good next step towards isolating the variable $\displaystyle t$?
I would finish it as:
$\displaystyle e^{-0,021t}=\frac{4}{9}$
$\displaystyle e^{0,021t}=\frac{9}{4}$
$\displaystyle 0,021t=\ln\left(\frac{9}{4} \right)=2\ln\left(\frac{3}{2} \right)$
$\displaystyle t=\frac{2000\ln\left(\frac{3}{2} \right)}{21}\approx38.6157245817$