In the figure a reversible heat engine (HE) receives 600 kW from the source and rejects heat to the atmosphere. Its entire work output drives a reversible heat pump (HP) that takes heat from the atmosphere and delivers heat to the hot-water tank. Determine (a) the work output of the engine (answer in kW), (b) the heat delivered to the hot-water tank, Q_{4} (answer in kW) and (c) the net heat taken from the atmosphere, Q_{3} − Q_{2} (answer in kW). Show that the total entropy change of the three reservoirs is zero.