Solution:
(i)
$$\begin{tabular}{|l|l|}
\hline Marks Obtained & No. of students (c.f.) \\
\hline less than 10 & 8 \\
\hline less than 20 & 25 \\
\hline less than 30 & 38 \\
\hline less than 40 & 50 \\
\hline less than 50 & 67 \\
\hline
\end{tabular}$$
Steps Of construction:
(a) We need to plot the points (10, 8), (20, 25), (30, 38), (40, 50) and (50, 67) on the graph.
(b) Now join them with free hand to obtain an ogive.
(ii)
$$\begin{tabular}{|l|l|}
\hline Age in years (less than) & \begin{tabular}{l}
Cumulative \\
Frequency \\
\hline 10 & 0 \\
\hline 20 & & 17 \\
\hline 30 & 32 \\
\hline 40 & 37 \\
\hline 50 & 53 \\
\hline 60 & 58 \\
\hline 70 & & 65 \\
\hline
\end{tabular} \\
\hline
\end{tabular}$$
Steps Of construction:
(a) We need to plot the points (10, 0), (20, 17), (30, 32), (40, 37), (50, 53), (60, 58) and (70, 65) on the graph.
(b) Now join them with free hand to obtain an ogive.