We will investgate the cost of a driveway on square foot basis.
A driveway is modeled as a rectangle with elementary side lengths defined as follows:
[tex]\begin{gathered} \text{Length ( L ) = 40 ft} \\ \text{Width ( w ) = 15 ft} \end{gathered}[/tex]The rate for contructing a driveway per square foot is gvien as follows:
[tex]\text{Rate = }\frac{\text{\$}3.5}{ft^2}[/tex]To determine the total cost of the driveway with the defined side lengths we need to consider the area ( A ) covered by the entire driveway. We will model the driveway in shape of a rectangle with the following area:
[tex]A\text{ = L}\cdot w[/tex]Plug in the respective side-lengths and determine the area ( A ) as follows:
[tex]\begin{gathered} A\text{ = 40}\cdot15 \\ A=600ft^2 \end{gathered}[/tex]Next we will determine the total cost of constructing a driveway with a covered area ( A ) as follows:
[tex]\text{Cost of driveway = A}\cdot Rate[/tex]Plug in the respective quantities and evaluate the cost or the amount Kelly pays:
[tex]\begin{gathered} Costofdriveway=600ft^2\cdot\frac{3.5}{ft^2} \\ \\ \text{Cost of driveway = \$2,100 } \end{gathered}[/tex]Hence, Kelly pays $2,100!