A heat engine operates with the cold reservoir at temperature 324   K . The minimum temperature of the…

A heat engine operates with the cold reservoir at temperature $324 \mathrm{K}$. The minimum temperature of the hot reservoir, if the heat engine takes $300 \mathrm{J}$ heat from the hot reservoir and delivers $180 \mathrm{J}$ heat to the cold reservoir per cycle, is _____  $K$.