An open end mercury manometer was constructed from a u-shaped tube. in a particular measurement, the level in the end connected to the gas manifold, on which the experiment was being conducted, measured 76.2 cm above the u-neck, while the level in the open end (to the atmosphere) was 23.8 cm above the u-neck. the outside air pressure in the laboratory was measured as 754 torr. what is the pressure in the gas manifold?