The following results were obtained from a 1-D consolidation test for a specimen of 2 cm thick with double drainage under an increase of pressure from 50 kPa to 100 kPa: Time Dial gauge reading (mm) 0.0 0 0.1 0.25 0.5 1.0 2.0 4.0 8.0 16.0 30.0 60.0 120.0 240,0 480.0 960.0 1440.0 0.105 0.125 0.15 0.1875 0.245 0.3175 0.4375 0.5875 0.75 0.9325 1.0875 1.2125 1.2875 1.3375 1.3675 a) Find the coefficient of consolidation by both the log-t and method. Comment on the results. b) Using the average value of c. from (a), calculate the time required to reach 50% and 90% consolidation and the corresponding height of the sample at those moments.