Answer with Explanation:
We know that by Gauss's Law

Where 
 is permitivity of free space
 is permitivity of free space
 is the net charge in the hull
 is the net charge in the hull
Part a)
Applying the given values we get

Part b)
Since the sign of the electric flux is negative we conclude that the electric field lines entering the submarine are more than the electric field lines leaving the submarine. Since negative sign implies that flux by negative charges is dominant.