how do i solve for t:

Question

-.50=1-e^-(t/125)^5

i got this far:

ln(.5)=5ln(-t/125)

t=?

Answer 1

5 e^-(t/5^2) = 1.5
e^-(t/125) = .3
e^(t/125) = 1/.3 = 3.3333
t/125 = ln 3.3333
t = 150.5