Dry milk powder is produced in a certain plant producing whole milk having solids content of $13\%$ into a vacuum pan evaporator where the solids content is increased to $30\%.$ The concentrated milk then enters the spray dryer. The milk solid having a moisture content of $5\%$ then leave the dryer at the rate of $900$ kg$/$h to be begged. Calculate :The mass flow rate of the whole milk into the vacuum pan evaporator, the concentrated milk from the vacuum pan evaporator to the spray dryer and the water vapour from the spray dryer.