Solution:

(i)
$$\begin{tabular}{|l|l|l|}
\hline Class Interval (Inclusive form) & Class Interval (Exclusive Form) & Frequency \\
\hline $30-39$ & 29.5-39.5 & \\
\hline $40-49$ & 39.5-49.5 & 24 \\
\hline $50-59$ & 49.5-59.5 & 16 \\
\hline $60-69$ & 59.5-69.5 & 09 \\
\hline $70-79$ & 69.5-79.5 & 15 \\
\hline
\end{tabular}$$

Steps of construction:

(a) We need to convert the data into exclusive form. [Here, adjustment factor $=0.5$ ]

(b) By taking suitable scales, mark the class intervals on $x$-axis and
the frequency on $y$-axis.

(c) Now, construct rectangles with class intervals as bases and corresponding frequencies as heights.

(ii)
From the data given:
$$\begin{tabular}{|l|l|l|}
\hline Class Marks & Class Intervals & Frequency \\
\hline 16 & $12-20$ & 08 \\
\hline 24 & $20-28$ & 12 \\
\hline 32 & $28-36$ & 15 \\
\hline 40 & $36-44$ & 18 \\
\hline 48 & $44-52$ & 25 \\
\hline 56 & $52-60$ & 19 \\
\hline 64 & $60-68$ & 10 \\
\hline
\end{tabular}$$

Steps of construction:
(a) Firstly, we need to convert the class marks into class intervals.

(b) Now, by taking suitable scales, mark class intervals on $x$-axis and frequency on $y$-axis.

(c) Now, construct rectangles with class intervals as bases and corresponding frequencies as heights.