4. From two permeability tests it is found that the void ratio and hydraulic conductivity of a normally consolidated clay are 1.45 and 0.7x10-7 cm/sec respectively, and 1.55 and 1.55 x 10-7 cm/sec respectively. Estimate the permeability coefficient at a void ratio of 1.5. Use Samarasinghe, Huang and Drenevich relationship