Answer
$50.3h$
Work Step by Step
We can find the required time as follows:
$Q=mc_{water}\Delta t+mL_f$
We plug in the known values to obtain:
$Q=(865Kg)[4186J/Kg.K(20^{\circ}C)+(33.5\times 10^4)J/Kg]$
$Q=3.62\times 10^8J$
Now $t=\frac{Q}{P}$
We plug in the known values to obtain:
$t=\frac{3.62\times 10^8J}{2000J/s}(\frac{1h}{3600s})$
$t=50.3h$
