how to put two figures, side by side proportionally, in a latex file

two-figures.tex

\usepackage{multirow,array}
\usepackage{floatrow}
% in combination with floatrow for properly adjusted figures, placeins ensures said figures appear
% where they are declared within the latex code, i.e. in subsection Part I of this paper. For proper
% usage with subsections, MUST use \FloatBarrier command after done with a figure
\usepackage[section]{placeins}
% ensures captions are properly centered under their respective figures
\usepackage[justification=centering]{caption}
% special command for table captions
\newfloatcommand{capbtabbox}{table}[][\FBwidth]

\begin{document}

\begin{figure}
  \begin{floatrow}    
\ffigbox{%
  \includegraphics[width=0.75\linewidth]{supply-demand-basic.png}
}{%  
  \caption[]{Classic supply \& demand diagram}%
}
\end{floatrow}
\end{figure}
\begin{figure}
  \begin{floatrow}    
\capbtabbox{%
    \setlength{\extrarowheight}{2pt}
    \begin{tabular}{cc|c|c|}
      & \multicolumn{1}{c}{} & \multicolumn{2}{c}{Prisoner $Y$}\\
      & \multicolumn{1}{c}{} & \multicolumn{1}{c}{$Silent$}  & \multicolumn{1}{c}{$Snitch$} \\\cline{3-4}
      \multirow{2}*{Prisoner $X$}  & $Silent$ & $(1.0, 1.0)$ & $(0.0, 0.75)$ \\\cline{3-4}
      & $Snitch$ & $(0.75, 0.0)$ & $(0.25, 0.25)$ \\\cline{3-4}
      \vspace{20.0 pt} % if you want to shift the table
    \end{tabular}
}{%
  \caption{Classic single iteration Prisoner's Dilemma payoff matrix}%
}
\end{floatrow}
\end{figure}
\FloatBarrier

\end{document}