Eric is using his printer to print a rectangular photograph measuring $8$ inches by $10$ inches. Unfortunately, the printer starts running out of ink as soon as Eric puts the paper in$,$ so the density of ink on the final photograph varies with distance to one of the $8$ inch sides. If the ink density is given by $(x)ml$ per square inch, where $x$ is distance to one of the $8$ inch sides, write a Riemann sum that approximates the total amount of ink on the photograph. $($Start by slicing into $n$ slices; your final approximation should be in terms of $n.)$