At a certain depth below the foundation of a building there is a stratum of clay 4.0 a thick with incompressible permeable soil above and below it. In a consolidation test on this clay sample initially 2.5 cm thick was compressed under a steady pressure. Half de final settlement took place in the first 16 minutes after application of the pressure. stimate how long it will take for the settlement of the building to reach 50% of its ultimate arie.