In a cycle that regeneratively produces steam, only water is fed to the heater. $4500$ to steam turbine

It enters with kPa and $500$oC temperature and exits with $20$ kPa. $350$ kPa from the steam turbine fed to the heater

and the temperature of the condenser lowers the condensation temperature of the feed water at $350$ kPa pressure.

$6\backslash$deg C increases. If the efficiency of the turbine and pump is $0\mathrm{.}78,$ what is the thermal efficiency of the cycle? entering the turbine

How much of the steam is separated from the water fed to the heater?