The formula of the perimeter of a rectangle is
[tex]P=2l+2w[/tex]where l and w are the length and width of the rectangle, respectively.
In our case,
[tex]A=76,l=20[/tex]Thus,
[tex]\begin{gathered} \Rightarrow76=2w+2(20) \\ \Rightarrow76-40=2w \\ \Rightarrow w=\frac{36}{2}=18 \\ \Rightarrow w=18 \end{gathered}[/tex]The width of the garden is 18ft
