Determine the number of classes in the frequency table below.

[tex]\begin{tabular}{rr}
\hline Class & Frequency \\
[tex]38-39[/tex] & 7 \\
[tex]40-41[/tex] & 2 \\
[tex]42-43[/tex] & 6 \\
[tex]44-45[/tex] & 4 \\
[tex]46-47[/tex] & 1 \\
\hline
\end{tabular}[/tex]
20
6
5
2