Answer
Please see the work below.
Work Step by Step
We know that
$Q=mL_f$
We plug in the known values to obtain:
$Q=(20)(334000)$
$Q=6680000J$
Now we can find the power as
$P=\frac{Q}{t}$
We plug in the known values to obtain:
$P=\frac{6680000}{(6.0)(60)}$
$P=19000W$
