A vacuum gage at the intake duct to a fan gives a reading of 4.5 in. of

Question:

A vacuum gage at the intake duct to a fan gives a reading of 4.5 in. of manometer fluid. The surrounding atmospheric pressure is 14.5lbf/in2. Determine the absolute pressure inside the duct, in lbf/in2. The density of the manometer fluid is 49.94 lb/ft3, and the acceleration of gravity is 32.2 ft/s2