Consider an air$-$standard jet engine cycle operating in a $280K,100-$kPa environment. The compressor requires a shaft power input

of $4000$ kW $.$ Air enters the turbine state $3$ at $1500$ K and $2$ MPa $,$ at the rate of $9k\frac{g}{s},$ and the isentropic efficiency of the turbine is

$90\%.$ Determine the pressure $($KPa$)$ entering the nozzle. Use the air standard method.