#### Answer

$\frac{3}{16}$ in

#### Work Step by Step

Lets consider the thickness of the steel plates are $\frac{7}{16}$ in and $\frac{5}{8}$ in
therefore the difference in thickness = $\frac{5}{8}$ - $\frac{7}{16}$
=$\frac{5}{8}\times$ $\frac{2}{2}$ - $\frac{7}{16}$
=$\frac{10}{16}$ - $\frac{7}{16}$
=$\frac{3}{16}$ in