A constant-head test was conducted on a sample of soil 15 cm long and 60 cm2 in cross-sectional area. The quantity of water collected was 50 cm3 in 20 seconds under a head difference of 24 cm. Calculate the hydraulic conductivity. If the porosity of the sand is 55%, calculate the average velocity and the seepage velocity. Estimate the hydraulic conductivity of a similar soil with a porosity of 35% from the results of this test.