We have been given that professional plumbers suggest that a sewer pipe should be sloped 0.25 inch for every foot.
Therefore, we can find the slope as:
[tex]\text{Slope}=\frac{0.25\text{ inch}}{\text{1 foot}}=\frac{0.25\text{ inch}}{\text{12 inch}}[/tex]
[tex]\text{Slope}=\frac{0.25}{12}=\frac{25}{1200}=\frac{1}{48}[/tex]
Therefore, the recommended slope for a sewer pipe is [tex]\frac{1}{48}[/tex]
