SOLUTION
Step 1: Find the area of the wall.
[tex]\begin{gathered} A=l\times b \\ A=42\times25.5 \\ A=1071ft^2 \end{gathered}[/tex]
Step 2: Find the cost of wallpaper per square foot
[tex]=\frac{total\text{ cost of wallpaper}}{Area\text{ of the wall}}[/tex][tex]\begin{gathered} =\frac{771.12}{1071} \\ =0.72\text{ dollars} \end{gathered}[/tex]
The correct answer is B: $0.72
