NCERT Solutions for Class 7 Maths Chapter 3 Exercise 3.3

Q.1 Use the bar graph (Fig below) to a answer the following question
(a) Which is the most popular pet?
(b) How many children have dog as a pet?

Ans.

(a) The bar showing cats is the tallest, so cat is the most popular pet.
(b) From the bar graph, the number of children having dog as a pet is 8.

Q.2

$$\begin{gathered} \text{Read the bar graph}\left(\text{Fig below}\right)\text{and answer the questions t} \\ \text{hat follow:} \end{gathered}$$

$$\begin{gathered} \text{Number of books sold by a book store during five} \\ \mathrm{consecutive}\mathrm{years}. \end{gathered}$$

Ans.

\begin{array}{l}\text{(i) In 1989, 175 books were sold in 1990, 475 books were sold}\text{.}\\ \text{In 1992, 225 books were sold}\text{.}\\ \text{(ii) From the graph, it can be concluded that 475 books were}\\ \text{sold in the year 1990 and 225 books were sold in the year 1992}\text{.}\\ \text{(iii) From the graph, it can be concluded that in the years}\\ \text{1989 and 1992, the number of books sold were less than 250}\text{.}\\ \text{(iv) From the graph, it can be concluded that the number of}\\ \text{books sold in the year 1989 is about 1 and}\frac{3}{4}\text{th}\text{part of 1 cm}\\ \text{The scale is taken as 1 cm = 100 books}\\ \text{So, 100+}\frac{3}{4}\times 100=100+75=175\\ \text{Therefore, about 175 books were sold in the year 1989}\text{.}\end{array}

Q.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?
(b) Answer the following questions:
(i) Which class has the maximum number of children? and the minimum?
(ii) Find the ratio of students of class sixth to the students of class eight.

Ans.

\begin{array}{l}\text{(a)}\text{Choose a scale as 1 unit = 10 children, because we can}\\ \text{show a clear difference between the number of students of}\\ \text{class 7th and class 9th}\text{.}\\ \text{(b)}\\ \text{(i)}\\ \text{The bar representing the number of children of class fifth is}\\ \text{tallest, there are maximum number of children in class fifth}\\ \text{and the bar representing the number of children of class tenth is}\\ \text{smallest, there are minimum number of children in class tenth}\text{.}\\ \text{(ii)}\\ \text{The number of student in class sixth is 120 and the number of}\\ \text{student in class eight is 100}\text{.}\\ \text{So, the ratio ratio is =}\frac{120}{100}=\frac{20\times 6}{20\times 5}=\boxed{\frac{6}{5}}\end{array}

Q.4 The performance of student sin 1^st Term and 2^nd Term is given.
Draw a double bar graph choosing appropriate
scale and answer the following:

(i) In which subject, has the child improved h is performance the most?
(ii) in which subject is the improvement the least?
(iii) Has the performance gone down in any subject?

Ans.

\begin{array}{l}\text{(i) There was a maximum increase in the marks obtained in}\\ \text{Maths}\text{. Thus, the child improved his performance the most}\\ \text{in Maths}\text{.}\\ \text{(ii) From the graph, we observe that the improvment was least}\\ \text{in S}\text{. Science}\text{.}\\ \text{(iii) From the graph, we observe that the performance in Hindi}\\ \text{has grown down}\text{.}\end{array}

Q.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 graph?
(ii) Which sport is most popular?
(iii) Which is more preferred watching or participating sport?

Ans.

(i)

\begin{array}{l}\text{(ii) From the bar graph, the bar representing the number}\\ \text{of people who like watching and participating in cricket}\\ \text{is the tallest among all the bars}\text{.Thus, cricket is the most}\\ \text{popular sport}\text{.}\\ \text{(iii) The bars showing watchig spot are longer than the bars}\\ \text{showing participating in spot}\text{. Thus, watching different types}\\ \text{of sports is more preffered than participating in the sports}\text{.}\end{array}

Q.6 Take the data giving the mininum and the maximum temperature of various cities given in the beginning of this chapter.

Plot a double bar graph using thedata and answer the following:
(i) Which city has the largest difference in the minimum and maximum temperature on the given date?
(ii) Which is the hottest city and which is the coldest city?
(iii) Name two cities where maximum temperature of one was less than the minimum temperature of the other.
(iv) Name the city which has the least difference between its minimum and the maximum temperature.

Ans.

\text{A double bar graph for given data is shown as below:}

\begin{array}{l}\text{(i) From the graph, we observe that Jammu has the largest}\\ \text{difference in its minimum and maximum temprature on the}\\ \text{given date}\text{.}\\ \text{(ii) From graph, we observe that Jammu is the hottest city}\\ \text{and Banglore is the coldest city}\text{.}\\ \text{(iii) Banglore and Jaipur, Banglore and Ahemdabad}\text{.}\\ \text{For Banglore, the maximum temprature was 28}°C\text{, while}\\ \text{temprature of both cities was 29}°C.\\ \text{(iv) From graph, we observe that the city which has the}\\ \text{least difference between its minimum and maximum}\\ \text{temprature is Mumbai}\text{.}\end{array}