(a) Since the equation is:
[tex]p=0.8L[/tex]And "L" is in meters, the cos per meter will be simply the slope of the line. Alternatively, we can just input L = 1 and check the corresponding cost:
[tex]\begin{gathered} p=0.8\cdot1 \\ p=0.8 \end{gathered}[/tex]So, the cost is $0.80 per meter.
(b) Now, we have to the the contrary, we input 1 input "p" and calculate "L":
[tex]\begin{gathered} p=0.8L \\ 1=0.8L \\ L=\frac{1}{0.8} \\ L=1.25 \end{gathered}[/tex]So, it will be 1.25 meters long.
