Answer
The charge on the inner surface of the conducting shell is $~~-5.00~fC$
Work Step by Step
The electric field inside a conducting shell is zero.
We can draw a Gaussian sphere with a radius such that the surface of the Gaussian sphere is within the conducting shell.
The electric field at this radial distance is zero.
Therefore the flux through the sphere is zero.
We can find the charge on the inner surface of the conducting shell:
$\Phi = \frac{q_{enc}}{\epsilon_0} = 0$
$\Phi = \frac{5.00~fC+q}{\epsilon_0} = 0$
$q = -5.00~fC$
Therefore, the charge on the inner surface of the conducting shell is $~~-5.00~fC$
