Answer
170 mi
Work Step by Step
We have the proportion, using the fact that $4\frac{1}{4}=4.25$,
$$
\frac{1}{40}=\frac{4.25}{x}
.$$
By setting the product of the means and the product of the extremes equal, we have
$$
x=4.25\cdot 40\Longrightarrow x=170 \ mi
.$$
