A centrifugal pump having an impeller diameter of 0.40 m discharges 0.03 m^{3}/s against a total head of 20 m when running at 1500 rpm. Find (a) the head (m), (b) the discharge (m^{3}/s) and (c) the ratio of powers P_{1}/P_{2} of a geometrically similar pump of diameter 0.25 m running at 3000 rpm.