jmc

Looking at the graph, the line has a $y$-intercept of 3. Also, counting carefully, we can see that when the line travels exactly 7 units horizontally, it travels 4 units vertically. Therefore, the slope of the line is $4/7$. So, the equation of the line in slope-intercept form is $y=\frac{4}{7}x+3$. Substituting 1001 for $x$ and $n$ for $y$, we can find $n$: $$\begin{array}{rl}n& =\frac{4}{7}\cdot 1001+3\\ \Rightarrow n& =4\cdot 143+3\\ \Rightarrow n& =572+3=\boxed{575}.\end{array}$$