$3.$ A rigid tank containing $7\mathrm{.}3$ kg of ideal gas at $\backslash (13\mathrm{.}3^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ and $397$ kPa is connected through a valve to another rigid tank containing of $3\mathrm{.}1$ kg of same ideal gas air at $\backslash (37\mathrm{.}9^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash )$ and $204$ kPa $.$ The valve is opened, and the entire system is allowed to reach thermal equilibrium with the surroundings, which are at $\backslash (20\mathrm{.}1^\{\backslash$circ$\}\backslash$mathrm$\{$C$\}\backslash ).$ Determine the final equilibrium pressure of air. Write your answer in kPa with $2$ decimal figures. $($Please solve this question step by step and use handwriting.$)$