Thermodynamics & Heat Transfer Expert Needed

I'm seeking a seasoned mechanical engineer with a strong emphasis on thermodynamics and heat transfer. The primary focus of this project is to solve mechanical engineering problems.

Must have the capacity to solve such problem in a short time length:

Consider a turbogas plant characterized by the following operation process:
- the compressor draws in air (???
= 1.004 kJ/kgK , ?? = 1.4) from the environment (20 °C and 1 bar) and it
compresses it to a pressure of 9 bar, with a polytropic efficiency of 0.85;
- after being compressed, the air enters the combustion chamber, which has an efficiency of
90 %, and is mixed with the fuel;
- following combustion, the fluid (???
= 1.104 kJ/kgK , ?? = 1.35) reaches the
temperature of 850 °C and enters the turbine, which has an isoentropic efficiency of 0.8.
Assuming that a fuel with a lower heating value of 40 MJ/kg is used, calculate
the air-to-fuel ratio and the overall efficiency of the plant.