Answer 1

Class Interval (Inclusive from )	Class Interval (Exclusive from)	Frequency
30-39	29.5-39.5	24
40-49	39.5-49.5	16
50-59	49.5-59.5	09
60-69	59.5-69.5	15
70-79	69.5-79.5	20

Step of construction: 

(a) Convert the data into exclusive form. 

(b) Taking suitable scales, marks class interval on x-axis abd frequency on y-axis. 

(c) Construct rectangle with class intervals as  bases and corresponding frequencies as heights.