A reversible power cycle whose thermal efficiency is $40 \%$ receives $50 \mathrm{~kJ}$ by heat transfer from a hot reservoir at $600 \mathrm{~K}$ and rejects energy by heat transfer to a cold reservoir at temperature $T_{\mathrm{C}}$. Determine the energy rejected, in $\mathrm{kJ}$, and $T_{\mathrm{C}}$, in $\mathrm{K}$.