CBSE Class 8 Mathematics Introduction to Graphs Assignment Set 05

Question 1. Draw double bar graph for the following data showing the examination marks

Read the graph and answer the following questions
(a) Do you see any improvement?
(b) Who has not done better?
Answer:
Double Bar Graph Construction Steps:
1. Take a graph paper and draw two perpendicular axes: X-axis (horizontal) and Y-axis (vertical).
2. Along the X-axis, represent the students (A, B, C, D, E), leaving equal spaces between groups.
3. Along the Y-axis, represent the marks obtained, choosing a suitable scale (e.g., 1 unit = 5 marks).
4. For each student, draw two adjacent bars—one for the Quarterly Exam and one for the Half-yearly Exam—using different colors or shading with a legend.
(a) Yes, most students show improvement in their half-yearly exam marks compared to their quarterly exam marks.
(b) Student D has not done better, as their marks decreased from 48 in the quarterly exam to 45 in the half-yearly exam.
In simple words: Comparing the two exams, students A, B, C, and E improved their scores, while student D scored lower.

Exam Tip: Always include a proper scale, axis labels, and a clear legend when drawing double bar graphs.

Question 2. Draw a double bar graph for the following data showing the maximum and minimum temperature of cities.

Read the graph and answer the following questions
(i) Which city has the maximum difference in day's temperature?
(ii) Which are the hottest and the coldest city?
Answer:
Double Bar Graph Construction Steps:
1. Draw X-axis and Y-axis on graph paper.
2. Represent the cities (Delhi, Bangalore, Srinagar, Mumbai, Chennai) along the X-axis.
3. Represent the temperature in °C along the Y-axis using an appropriate scale (e.g., 1 unit = 5 °C).
4. Plot two bars side by side for each city to represent maximum and minimum temperatures.

Calculations for temperature difference (Max - Min):
- Delhi: \(35 - 25 = 10^\circ\text{C}\)
- Bangalore: \(20 - 18 = 2^\circ\text{C}\)
- Srinagar: \(10 - 2 = 8^\circ\text{C}\)
- Mumbai: \(30 - 25 = 5^\circ\text{C}\)
- Chennai: \(33 - 26 = 7^\circ\text{C}\)

(i) Delhi has the maximum temperature difference of \(10^\circ\text{C}\).
(ii) Hottest city is Delhi (Max temp \(35^\circ\text{C}\)) and Coldest city is Srinagar (Min temp \(2^\circ\text{C}\)).
In simple words: Delhi has the largest gap between its high and low temperatures, while Delhi is overall the warmest and Srinagar is the coldest.

Exam Tip: To find the temperature difference, always subtract the minimum temperature from the maximum temperature for each city.

Question 3. Draw a double bar graph for the following data showing the Hindi and English books bought by a library in a year.
 

Read the graph and answer the following questions
In which year the Hindi book max?
In which year the English book min?
Answer:
Double Bar Graph Construction Steps:
1. Set up horizontal X-axis for years (2008 to 2012) and vertical Y-axis for number of books.
2. Choose a suitable scale on the Y-axis (e.g., 1 unit = 100 books).
3. Draw pairs of bars for Hindi and English books corresponding to each year.
- Hindi books maximum: In the year 2012 (700 books).
- English books minimum: In the year 2008 (350 books).
In simple words: The highest number of Hindi books was purchased in 2012, and the lowest number of English books was purchased in 2008.

Exam Tip: Read the question carefully to identify whether it asks for maximum or minimum and for which specific subject.

Question 4. Draw a double bar graph for the following data showing the manufacture of cars of Maruthi and Hundai in various years.

Answer:
Double Bar Graph Construction Steps:
1. Draw horizontal X-axis for years (2006 to 2010) and vertical Y-axis for number of cars manufactured.
2. Choose a suitable scale on the Y-axis (e.g., 1 unit = 500 cars).
3. Draw pairs of bars for Maruti and Hyundai cars for each corresponding year.
In simple words: The bar graph visually compares the annual production numbers of Maruti and Hyundai cars from 2006 to 2010.

Exam Tip: Ensure proper spacing between consecutive years and distinct colors for each manufacturer to maintain clarity.