Determine the vane angle at the outer periphery of the impeller and label the angle by sketching the impeller

Question

A centrifugal pump is to discharge 0.2 m³/s at a speed of 1400 rpm against a head of 25 m. The impeller diameter is 0.3 m, its width at outlet is 0.05m and the manometric efficiency is 80%. Determine the vane angle at the outer periphery of the impeller and label the angle by sketching the impeller