Answer:
a

b

Explanation:
From the question we are told that
The area of Manhattan is 
The area of the ice is 
The thickness is 
Generally the volume of the ice is mathematically represented is

substituting value


Generally the mass of the ice is

Here
is the density of ice the value is 
=> 
=> 
Generally the energy needed for the ice to melt is mathematically represented as

Where
is the latent heat of fusion of ice and the value is 
=> 
=> 
Considering part b
We are told that the annual energy consumption is 
So the time taken to melt the ice is


converting to days
