280. A model pump delivering water at 180°F (γ = 60.6 lb/ ft3

; pvapor = 7.54 psia) at 900 gpm and

2500 rpm begins to cavitate when the inlet pressure and velocity are 13 psia and 22 fps. Find

the required NPSH of a prototype which is 4 times larger and runs at 1100 rpm.

A. 63.5 ft B. 20.49 ft C. 6.61 ft D. 36 ft