The perimeter of the flag is P = 500 ft.
Let the widt of the flag be w, then length of the flag is l = (30 + w).
The formula for the perimeter of the flag is,
[tex]P=2(l+w)[/tex]Substitute the expressions in the formula to obtain the dimensions of the flag.
[tex]\begin{gathered} 500=2(30+w+w) \\ 30+2w=250 \\ 2w=220 \\ w=\frac{220}{2} \\ =110 \end{gathered}[/tex]Determine the length of the flag.
[tex]\begin{gathered} l=110+30 \\ =140 \end{gathered}[/tex]So length of the flag is 140 feet and width of the flag is 110 feet.