\textbf{169-} If we reduce the cold source temperature of a heat engine that performs $100$ joules of work with a Carnot cycle by $20\%$, and increase $\eta$ by $20\%$, the temperature of the cold source of this engine is how many degrees Celsius?
(1) $500$ \hfill (2) $327$ \hfill (3) $300$ \hfill (4) $227$