#### Answer

$\frac{5}{16}$ in

#### Work Step by Step

To find the remaining thickness, subtract the depth of the holes from the depth of the base. Convert fractions to least common denominator and subtract the numerators.
$\frac{7}{8}-\frac{9}{16}=\frac{7\times2}{8\times2}-\frac{9}{16}=\frac{14}{16}-\frac{9}{16}=\frac{5}{16}$