NCERT Solutions for Class 7 Maths Chapter 3: Data Handling - Exercise 3.3

Exercise 3.3

1. Use the bar graph to answer the following questions:

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(a) Which is the most popular pet?

Ans: Since the bar representing cats is the tallest, Cat is the most popular pet.

(b) How many students have dog as a pet?

Ans: From the bar graph, 8 students have a dog as a pet.

2. Read the bar graph which shows the number of books sold by a bookstore during five consecutive years and answer the following questions:

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(i) About how many books were sold in 1989? 1990? 1992?

Ans: (a) In 1989, 180 books were sold.

(b) In 1990, 475 books were sold.

(c) In 1992, 225 books were sold.

(ii) In which year were about 475 books sold? About 225 books sold?

Ans: From the graph, in 1990, about 475 books were sold and in 1992, about 225 books were sold.

(iii) In which years were fewer than 250 books sold?

Ans: From the graph, it can be concluded that in 1989 and 1992 fewer than 250 books were sold.

(iv) Can you explain how you would estimate the number of books sold in 1989?

Ans: From the graph, it can be concluded that the number of books sold in the year 1989 is about 1 and \[\dfrac{3}{4}{\text{th }}\] part of \[{\text{1cm}}\].

We know that the scale is taken as \[{\text{1cm }} = {\text{ 100 books}}\].

\[100 + \dfrac{3}{4} \times 100 = 100 + 75 = 175\]

Therefore, about 175 books were sold in the year 1989.

3. Number of children in six different classes are given below. Represent the data on a bar graph.

(a) How would you choose a scale?

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Ans: We will choose a scale as 1 unit = 10 children because we can represent a more clear difference between the number of students of class 7th and that of class 9th by this scale.

(b) Answer the following questions:

(i) Which class has the maximum number of children? And the minimum?

Ans:  Since the bar representing the number of children for class fifth is the tallest, there are maximum number of children in class fifth. Similarly, since the bar representing the number of children for class tenth is the smallest, there are minimum number of children in class tenth.

(ii) Find the ratio of students of class sixth to the students of class eighth.

Ans: The number of students in class sixth is 120 and the number of students in class eighth is 100.

Therefore, the ratio \[{\text{ = }}\dfrac{{{\text{the number of students of class sixth}}}}{{{\text{the number of students of class eighth}}}}\]

\[ = \dfrac{{120}}{{100}} = \dfrac{6}{5} = 6:5\]

4. The performance of a student in \[{1^{st}}\] term and \[{2^{nd}}\] term is given. Draw a double bar graph choosing appropriate scale and answer the following:

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The difference of marks in both terms of each subject.

English \[ = 70 - 67 = 3\]

Hindi \[ = 65 - 72 =  - 7\]

Maths \[ = 95 - 88 = 7\]

Science \[ = 85--81 = 4\]

S. Science \[ = 75--73 = 2\]

(i) In which subject has the child improved his performance the most?

Ans: There was a maximum increase in the marks obtained in Maths, which is 7 marks. Therefore, the child has improved his performance the most in Maths.

(ii) In which subject is the improvement the least?

Ans: From the graph, it can be concluded that he only improved 2 marks in S.Science. Therefore, the improvement was the least in S. Science.

(iii) Has the performance gone down in any subject?

Ans: From the graph, it can be observed, in Hindi his marks decreased from 72 to 65. Therefore, in Hindi, his performance has gone down.

5. Consider this data collected from a survey of a colony.

(i) Draw a double bar graph choosing an appropriate scale. What do you infer from the bar graph?

Ans: A double bar graph for the given data is as follows.

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The double bar graph represents the number of people who like watching and participating in different sports. It can be observed that most of the people like watching and participating in cricket while the least number of people like watching and participating in athletics.

(ii) Which sport is most popular?

Ans: From the bar graph, it can be observed that the bar representing the number of people who like watching and participating in cricket is the tallest among all the bars. Hence, cricket is the most popular sport.

(iii) Which is more preferred, watching or participating in sports?

Ans: The bars representing watching sport are longer than the bars representing participating in sport. Hence, watching different types of sports is more preferred than participating in the sports.

6. Take the data giving the minimum and the maximum temperature of various cities given in the beginning of this Chapter. Plot a double bat graph using the data and answer the following:

(i) Which city has the largest difference in the minimum and maximum temperature on the given data?

Ans: A double bar graph for the given data is constructed as follows.

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From the graph, it can be concluded that Jammu has the largest difference in its minimum and maximum temperatures on 20.6.2006.

i.e. Maximum temperature \[ = \]\[{41^ \circ }{\text{C}}\] Minimum temperature \[ = \]\[{26^ \circ }{\text{C}}\]

Therefore, Difference \[ = {41^ \circ }{\text{C}} - {26^ \circ }{\text{C = }}{15^ \circ }{\text{C}}\]

(ii) Which is the hottest city and which is the coldest city?

Ans: From the graph, it can be concluded that Jammu is the hottest city due to maximum temperature and Bangalore is the coldest city due to lowest minimum temperature.

(iii) Name two cities where maximum temperature of one was less than the minimum temperature of the order.

Ans: Bangalore and Jaipur, Bangalore and Ahmedabad.

For Bangalore, the maximum temperature was \[{28^ \circ }{\text{C}}\], while minimum temperature of both cities, Ahmedabad and Jaipur, was \[{29^ \circ }{\text{C}}\].

(iv) Name the city which has the least difference between its minimum and the maximum temperature.

Ans: From the graph, it can be concluded that the city which has the least difference between its minimum and maximum temperatures is Mumbai.

i.e. Maximum temperature \[ = {32^o}{\text{C}}\]Minimum temperature \[ = {27^o}{\text{C}}\]

Therefore, Difference \[ = {32^o}{\text{C}} - {27^o}{\text{C}} = {5^o}{\text{C}}\]

Class 7 Maths Chapter 3 Data Handling – Chapter Overview

The chapter Data Handling in Maths deals primarily with observations that are represented in either tables or graphs or in lists. From here, you need to interpret the representation and answer the questions that follow. To ace this chapter, students need to be acquainted with the various ways of interpreting given data and extracting useful information from there.

Keeping in mind the convenience of students, we provide extensive NCERT Solutions for Class 7 Maths Chapter 3 to simplify the overall learning process. Our step by step solution is likely to help students gain an in-depth knowledge of the chapter as well as solve questions quickly. 

Here is an overview of all the exercises covered in this chapter, with a particular focus on Exercise 3.3.

Maths NCERT Solutions Class 7 Chapter 3 Exercise 3.3 – All Questions

Here, you are asked to solve six questions, and each question is explained in details hereunder:

• Exercise 3.3 Class 7 Maths – Question 1

You are given a bar graph in the first question, and two short questions are under it. You are required to study the graph and find which bar represents the highest value and the total value of all the bars given. 

Finding the highest value is easier as you only need to find the value of the tallest bar, and that is your answer. Similarly, the second short question demands you to add up all the values of all the bars given. Follow our NCERT Solutions for Class 7 Maths Chapter 3 for a more straightforward calculation of the same. 

• Class 7 Maths Chapter 3 Exercise 3.3 – Question 2

Four short questions are there with this bar graph; however, there are no lines matched with the respective values. Hence, students need to study the graph carefully and assign values accordingly. After that, they should calculate the values asked.

For your convenience, you can draw a separate table, jot down the values, and then start your calculations.

• NCERT Solutions for Class 7 Maths Chapter 3 Exercise 3.3 – Question 3

Here, the data is given in a much simpler way in a table format. However, now you have to form the bar graph for the same data. Therefore, you can learn from our NCERT Solutions for Class 7 Maths Chapter 3 to find the class and rank concerning this data and solve the following three short questions. 

• Exercise 3.3 Class 7 Maths – Question 4

In this fourth question, the volume of provided data given is comparatively more, and you are asked to draw a double bar graph for the same. There are three short questions as well, which you need to calculate based on the chart. Make sure you draw the graph carefully and do not miss out on any data. 

• Class 7 Maths Chapter 3 Exercise 3.3 – Question 5

It is precisely similar to the previous questions with different data. You need to draw a double bar graph and solve for the two short questions that are a part of it. The answer to these questions can be determined from the graph that you draw. Finding the highest value will show which sport is most popular and hence help you derive the answer. 

• NCERT Solutions for Class 7 Maths Chapter 3 – Question 6

Question 6 is the last question of this exercise that comprises of a table with data on the temperature of four different places. Four short questions follow, and you have to draw a bar graph with the provided data and then answer those short questions.  

In our Maths NCERT Solutions Class 7 Chapter 3 Exercise 3.3, you can get the best tricks to deal with such data and also plot a graph with the same.

NCERT Solutions for Class 7 Maths Chapter 3 – Other Exercises

a) Chapter 3 Class 7 – Exercise 3.1

There are nine questions in all in this exercise, and since it is the introductory exercise, you will have to solve comparatively less complicated problems here. However, in case you still come across any doubt while answering, you can refer to our NCERT Solution for Class 7 Maths Chapter 3 Exercise 3.3. 

We have proper solutions to all the questions covered under this section in our study materials. They will not only help you in understanding the concepts effortlessly but also gain a stronghold on the same. Post-going through our solutions, you will be able to solve numerical that comes with a twist too.

b) Class 7 Chapter 3 – Exercise 3.2

The second exercise has five questions to be mastered by you. After calculating mean in the first exercise, here you will learn how to calculate both median and mode. You should understand that mean, median and mode are the fundamentals of data handling.

These three parameters are useful for a lifetime, and therefore, for a firm grasp on these, you should possess the necessary guidelines for active learning of the same. With our NCERT Solutions for Class 7 Maths Chapter 3, you can not only delve deeper into such concepts but also form the basis of statistics for advanced learning in the future as well. 

c) Chapter 3 Class 7 – Exercise 3.4

You are asked to solve only three questions in this last exercise. These questions are based on the concept of probability. It is crucial as well as an interesting section where you will learn about various terms and also a new way of handling data. 

Probability is the possibility of an event- the option of whether an event will occur or not. The basic of this topic is generally explained to students with the help of an example of dices or cards.   

Refer to our NCERT Solutions for Class 7 Maths Chapter 3 for clarity on such complex topics. It ensures that students can avoid getting confused between sample space and the overall possibility when two or more events are simultaneously occurring.

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