Oil (density 0.91 g/cm^3) flows in a pipe (see fig.) and the flow rate is measured via a mercury manometer (density of Hg=13.546 g/cm^3). If the difference in height between the two legs of the manometer is 0.78 in., what is the corresponding pressure difference between points A and B, in mmHg. At which point (A or B) is the pressure higher, and why? The temperature is 60 °F throughout.