We know that,

Charge given to any conductor appears entirely on its outer surface evenly.

Therefore, if equal amount of charge Q are given to a hollow and solid spheres, the entire charge Q will appear on their spherical surfaces and since they both have equal radius, capacitance of both spheres are given by

C=4πϵ₀ R

Where

R= radius of the spherical capacitor.

Now, using

We get

∴ Potential of both the spheres hollow and solid) will be same.