Answer
$3\frac{27}{32} \text{ inches}$
Work Step by Step
The inside diameter of the pipe can be found by subtracting twice the thickness of its wall to its outside diameter.
Thus,
Outside diameter
$\\=4\frac{9}{32}-2\times \frac{7}{32}
\\=4\frac{9}{32} - \frac{14}{32}
\\=(3+1+\frac{9}{32})-\frac{14}{32}
\\=3+\frac{32}{32}+\frac{9}{32}-\frac{14}{32}
\\=3+\frac{41}{32}-\frac{14}{32}
\\=3+\frac{41-14}{32}
\\=3+\frac{27}{32}
\\=3\frac{27}{32} \text{ inches}$
