\begin{tabular}{|l|l|}
\hline
\begin{tabular}{l}
Computers sold \\
(classes)
\end{tabular} & Frequency (fi) \\
\hline [tex]$3\ \textless \ 9$[/tex] & 2 \\
\hline [tex]$9\ \textless \ 15$[/tex] & 5 \\
\hline [tex]$15\ \textless \ 21$[/tex] & 10 \\
\hline [tex]$21\ \textless \ 27$[/tex] & 5 \\
\hline [tex]$27\ \textless \ 33$[/tex] & 3 \\
\hline
\end{tabular}

Complete the table and calculate the following:
(i) mean
[3 Marks]