Hi there!
Recall the equation for electric potential of a point charge:

V = Electric potential (V)
k = Coulomb's Constant(Nm²/C²)
Q = Charge (C)
r = distance (m)
We can begin by solving for the given electric potentials. Remember, charge must be accounted for. Electric potential is also a SCALAR quantity.
Upper right charge's potential:

Lower left charge's potential:

Add the two, and subtract from the total EP at the point:

The remaining charge must have a potential of 2036.25 V, so:

Answer:
Current = 8696 A
Fraction of power lost =
= 0.151
Explanation:
Electric power is given by

where I is the current and V is the voltage.

Using values from the question,

The power loss is given by

where R is the resistance of the wire. From the question, the wire has a resistance of
per km. Since resistance is proportional to length, the resistance of the wire is

Hence,

The fraction lost = 
To develop this problem it is necessary to apply the concept of Frequency based on speed and wavelength.
According to the definition the frequency can be expressed as

Where,
v = Velocity
Wavelength
Our value are given by,
v = 345m/s

Replacing


Therefore the frequency of the tuning fork is 547.61Hz