Correct. Finding the remaining space requires you to subtract the volume of the small cone, $\displaystyle\frac{{{160}\pi{{x}}^{{3}}}}{{3}}\usepackage{cmbright}\Huge\$ , from the volume of the large cone, $\displaystyle\frac{{{2500}\pi{{x}}^{{3}}}}{{3}}\usepackage{cmbright}\Huge\$ .