A centrifugal pump has an impeller of 80 cm in diameter and it delivers 1 m3/sec against a head of 80 m. The impeller runs at 1000 rpm and the width at outlet is 8 cm. If the leakage loss is 3 percent of the discharge, external mechanical loss is 10 KW and the hydraulic efficiency is 80 percent, calculate the blade angle at outlet, the power required and overall efficiency of the pump.