Answer
Please see the work below.
Work Step by Step
We know that
$K_b=\frac{K_w}{K_a}$
$K_b=\frac{1.0\times 10^{-4}}{4.8\times 10^{-13}}=2.08\times 10^{-2}$
As $K_b=\frac{K_w}{K_a}$
$K_b=\frac{1.0\times 10^{-14}}{1.1\times 10^{-12}}=9.09\times 10^{-13}$