The January 2013 Physics Challenge for Teachers and Students has some features that are surprising and worth a closer look. The problem concerns a Carnot-cycle refrigeration unit operating inside a tent. It achieves dynamic equilibrium with a freezer ("cold") compartment temperature of T[subscript C] = 13°C, tent temperature of T[subscript H] = 1°C (the "hot" waste side of the freezer), and temperature "outside" of the tent of T[subscript O] = 0°C. The problem is to find the equilibrium temperature inside the tent if an identical freezer is brought in and run simultaneously. As explained here, what constitutes an identical freezer is open to interpretation.