Answer
$25.51\;atm$
Work Step by Step
The difference between an absolute pressure and an atmospheric pressure is called the gauge pressure.
Therefore, the gauge pressure is given by
$P_{g}=\rho gh$
Substituting the given values
$P_{g}=1030\times9.81\times255\;Pa$
or, $P_{g}=\frac{1030\times9.81\times255}{1.01\times10^{5}}\;atm$
or, $\boxed{P_{g}=25.51\;atm}$
