A constant head permeameter has a sediment sample with a cross sectional area of 100 cm^2. The sediment sample is 30 cm long. The porous plates on top and bottom of the sample holding it in place have a vertical hydraulic conductivity of 0.001 cm/s and each have a thickness of 10 cm. At a head of 50 cm, the permeameter discharges 40 cm^3 in 900 sec.
Determine the hydraulic conductivity of the soil sample in cm/s.