Let $\displaystyle{x}=\usepackage{cmbright}\Huge\$ the first length and $\displaystyle{y}=\usepackage{cmbright}\Huge\$ the second length.

The two lengths add up to 240 inches, so $\displaystyle{x}+{y}={240}\usepackage{cmbright}\Huge\$ .

One piece is 4 times the length of the other, so $\displaystyle{x}={4}{y}\usepackage{cmbright}\Huge\$ .