Answer
$$2 Ms$$
Work Step by Step
We know that the equation for time is given by:
$$ t = \frac{Q}{P}$$
We substitute a different equation for Q:
$$t= \frac{mc \Delta T}{P}$$
We know that the numerical value for mass is equal to the number of liters of water, so:
$$m = \pi r^2 d \times 1000 Kg$$
This gives:
$$t= \frac{ \pi r^2 d \times 1000c \Delta T}{P}$$
where d is the depth of the water
We plug in the given values to find:
$$2 Ms$$