A feed rate of 200 gpm of a hydrocarbon mixture at 70C is being pumped from a tank at 1 atm abs pressure to a distillation tower. The density of the feed is 46.8 lbm/ft3 and its vapor pressure is 8.45 psia. The velocity in the inlet line to the pump is 3 ft/s and the friction loss between the tank and pump is 3.5 ft of fluid. The net positive suction head required is 6 ft.

a. How far below the liquid level in the tank must the pump be to obtain this required (NPSH)R?