STEP 1:
We'll derive an expression for the width and the length
[tex]\begin{gathered} w=\frac{2l}{3}\text{ where} \\ w\text{ = width} \\ l=\text{ length} \end{gathered}[/tex]STEP 2:
Next, We then derive an expression for the perimeter substituting w as a function of l
[tex]\begin{gathered} \text{Perimeter = 2(l+w)} \\ 240=2(l+\frac{2l}{3}) \end{gathered}[/tex]STEP 3:
Solve for l and subsequently w
[tex]\begin{gathered} \text{Perimeter}=\text{ 240 = 2(}\frac{2l+3l}{3})=2(\frac{5l}{3}) \\ 240=\frac{10l}{3} \\ \text{Cross multiplying gives 240}\times3=5l \\ l=\frac{240\times3}{10}=72ft \\ w=\frac{2l}{3}=\frac{2\times72}{3}=48ft \end{gathered}[/tex]Therefore, length = 72 ft and width = 48ft
