In a simple Brayton cycle, the pressure ratio is $8$ and temperatures at the entrance of compressor and turbine are $300$ $K$ and $1400$ $K$, respectively. Both compressor and gas turbine have isentropic efficiencies equal to $0.8$. For the gas, assume a constant value of $c_p$ (specific heat at constant pressure) equal to $1$ $kJ$/$kgK$ and ratio of specific heats as $1.4$. Neglect changes in kinetic and potential energies.

The thermal efficiency of the cycle in percentage (%) is

- $24.8$
- $38.6$
- $44.8$
- $53.1$