Answer
.0827
Work Step by Step
$\log {(1-k)} = -.3/H$
$H=8$
$\log {(1-k)} = -.3/H$
$\log {(1-k)} = -.3/8$
$\log {(1-k)} = -.0375$
We can rewrite the equation as follows:
$10^{-.0375} =1-k$
$.917276 = 1-k$
$.917276+k-.917276=1-k+k-.917276$
$k = .082724$
$k=.0827$