Using a joint variation equation $\displaystyle{V}={l}{w}{h}\usepackage{cmbright}\Huge\$ , substitute the values for the original box.

$\displaystyle{240}={k}{\left({8}\right)}{\left({2}\right)}\usepackage{cmbright}\Huge\$

$\displaystyle{k}={15}\usepackage{cmbright}\Huge\$

Use 15 in the next joint variation equation to find the volume of the modified box.

$\displaystyle{V}={15}{\left({6}\right)}{\left({3}\right)}={270}\usepackage{cmbright}\Huge\$