A test feed containing 200 kg of solid is separated by a hydrocyclone and the particle size distribution in feed and underflow are given below: Size range, um Feed size distribution Underflow size distribution 6.6-9.4 0.05 0.015 9.4-13.3 0.20 0.139 13.3-18.7 18.7-27.0 27.0-37.0 37.0-53.0 0.35 0.25 0.10 0.05 0.366 0.30 0.12 0.06 Measurement gave the mass of solid collected from underflow is 166.5 kg. (1) Find the total collection efficiency. (2) Determine the size distribution in the overflow. (3) Plot the grad efficiency curve for this device and determine the possible x50.