Steps to determine the brake (bhp) and motor horsepower (mhp):
1) Determine water horsepower (whp).
hA (Qgpm) (SG) / 3956 OR hA (Qcfs) (SG) / 8.814
2) Apply the pump efficiency given in the problem into the brake horsepower equation along with the whp to determine bhp.
bhp = (whp/pump efficiency)
pump efficiency = (whp/bhp) 100
3) Apply the motor efficiency given in the problem into the motor horsepower equation along with the bhp to determine mhp.
mhp = (bhp/motor efficiency)
motor efficiency = (bhp/mhp) 100