Steam is supplied to a turbine at 5.4 MPa, 300°C expanded isentropically to an exhaust pressure at 105.3 kPa. To what pressure must the incoming steam be throttled in order to reduce the work done per...

Steam is supplied to a turbine at 5.4 MPa, 300°C expanded isentropically to an exhaust pressure at 105.3 kPa. To what pressure must the incoming steam be throttled in order to reduce the work done per kilogram to two third of the work obtained without throttling? Assume the flow through the turbine is still reversible adiabatic and exhaust pressure is also same.