Two Carnot engines A and B are operated in series. Engine A receives heat from a reservoir at 600 K and rejects heat to a reservoir at temperature T. Engine B receives heat rejected by engine A and in turn rejects it to a reservoir at 100 K. If the efficiencies of the two engines A and B are represented by $$\eta_A$$ and $$\eta_B$$ respectively, then what is the value of $$\frac{\eta_A}{\eta_B}$$?