Answer
$\Delta P=-\rho _{2}gh-\rho _{1}gh=-\left( 0.87\times 10\times 7.6\times 10^{3}\right) -10^{3}\times 10\times 20=-266120Pa$
Work Step by Step
$$\Delta P=-\rho _{2}gh-\rho _{1}gh=-\left( 0.87\times 10\times 7.6\times 10^{3}\right) -10^{3}\times 10\times 20=-266120Pa$$