Question

In a public library, the following observations were recorded by the librarian in a particular week:

Days	Mon	Tues	Wed	Thurs	Fri	Sat
Newspaper Readers	400	600	350	550	500	350
Magazines Readers	150	100	200	300	250	200

1. Draw a double bar graph choosing an appropriate scale.
2. On which day, the number of readers in the library was maximum?
3. What is the mean number of magazine readers?

Answer 1

a. Steps to construct the bar graphs are as follows:

Step I: We draw two lines perpendicular to each other on graph paper and call them horizontal and vertical axes.

Step II: Along the horizontal axis, we mark the days and along the vertical axis, we mark the readers.

Step III: We choose a suitable scale to determine the heights of bars. Here, we choose the scale as 1 small division to represent 50.

Step IV: First, we draw the bars for newspaper readers and then bars for magazine readers for different days.

Bars for newspapers and magazine readers are shaded separately and the shading is shown in the top right corner of the graph paper.

b. Total number of both readers in different days are

Day	Readers
Mon	400 + 150 = 550
Tue	600 + 100 = 700
Wed	350 + 200 = 550
Thur	550 + 300 = 850
Fri	500 + 250 = 750
Sat	350 + 200 = 550

 Hence, it is clear that the number of readers was maximum on Thursday.

c. Mean of readers = `"Sum of all the magazine readers on six days"/6`

= `(150 + 100 + 200 + 300 + 250 + 200)/6`

= `1200/6`

= 200