A manometer is used to measure the pressure difference between two pipes A and B filled with

water at pressure $p_A$ and $p_B,$ respectively. The manometer contains mercury and oil as depicted

below. Note: ${}_{\text{w}\text{a}\text{t}\text{e}\text{r}}=1\mathrm{.}94$ slug $\frac{?}{f{t}^3},{}_{Hg}=26\mathrm{.}38$ slug $\frac{?}{f{t}^3},{}_{\text{o}\text{i}\text{l}}=1\mathrm{.}55$slu$\frac{g}{f}{t}^3.$

Find the pressure difference $p_A-p_B$ in $l\frac{b}{i}{n}^2.$