A solid sphere and a hollow sphere of same material have same mass. When they are heated by 50°C increase in volume of solid sphere is 5 cc. The expansion of hollow sphere is ...

$∆\mathrm{V}=\mathrm{V}.\mathrm{\gamma }.∆\mathrm{t}$

 $\therefore$Change in volume is proportional to the initial volume.
Now, for the mass being same, the hollow sphere will have bigger volume.
So, if 5 cc is the increase of volume for the solid sphere, increase of volume will be more than 5 cc for hollow sphere.