transport phenomena

3) An MRS service station attendant accidentally spills 20 liters of gasoil of density 800kg3m3, which quickly spreads over a concrete flat area of 2.33m2. Estimate the time required for the gasoil to evaporate into quiescent dry air; Dgu=0.604m2/hr. The temperature is 21C, and it may be assumed that the evaporation takes place through a film 15.24cm thick. The vapour pressure of the gasoil is 0.136 atmosphere. Take the density of gasoil vapour and dry air to be the same as that of dry air, (rho)=10.0kg/m3