Seawater containing 3.50 wt% salt passes through a series of 10 evaporators. Roughly equal quantities of water are vaporized in each of the 10 units and hen condensed and combined to obtain a product stream of fresh water. The brine leaving each evaporator but the tenth is fed to the next evaporator. The brine leaving the tenth evaporator contains 5.00 wt% salt. Determine the fractional yield of fresh water from the process (kg H2O recovered/kg H2O in process feed) and the fraction of salt in the solution leaving the fourth evaporator.