Problem $07\mathrm{.}088.$a $-$ Entropy change of air assuming constant specific heats

Determine the entropy change of air assuming constant specific heats. The gas constant of air is $\backslash ($ R$=0\mathrm{.}287\backslash$mathrm$\{$~kJ$\}/\backslash$mathrm$\{$kg$\}\backslash$cdot $\backslash$mathrm$\{$K$\}\backslash ).($Round the final answer to three decimal places.$)$

The entropy change of air is

kJ$/$K$.$