Can someone please help me rearrange this formula to find t.



0.4=1.2(1-e^(-t/2) )

\frac{2}{5}=\frac{6}{5}\left(1-e^{\frac{-t}{2}}\right)

Multiply both sides by 5/6.

\frac{1}{3}=1-e^{\frac{-t}{2}}

Subtract 1 from both sides:

\frac{2}{3}=e^{\frac{-t}{2}}

Now, take ln of both sides and finish up?