Connecting the Dots Class 7 Short Question Answer

Connecting the Dots Class 7 Short Question Answer

Connecting the Dots Class 7 Short Question Answer

Question 1.

The bar graph shows the result of a survey to test water resistant watches made by different companies.

Each of these companies claimed that their watches were water resistant. After a test, the above results were revealed.

(a) Can you work out a fraction of the number of watches that leaked to the number tested for each company ?

Solution:

A fraction of the number of watches that leaked to the number tested for each company are :

For A, [latex]\frac {20}{40}[/latex] = [latex]\frac {1}{2}[/latex]

For B, [latex]\frac {40}{10}[/latex] = [latex]\frac {1}{4}[/latex]

For C, [latex]\frac {15}{10}[/latex] = [latex]\frac {3}{8}[/latex]

and For D, [latex]\frac {25}{40}[/latex] = [latex]\frac {5}{8}[/latex]

(b) Could you tell on this basis which company has better watches ?

Solution:

Clearly, 10 < 15 < 20 < 25.

⇒ [latex]\frac {10}{40}[/latex] < [latex]\frac {15}{40}[/latex] < [latex]\frac {50}{40}[/latex] < [latex]\frac {20}{40}[/latex]

Thus, company with fraction [latex]\frac {40}{10}[/latex], i.e., company B has better watches.

Question 2.

Use the bar graph to answer the following questions.

(a) Which is the most popular pet ?

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

Solution:

Clearly, from the given bar graph :

(a) The most popular pet is cat.

(b) Eight students have dog as a pet.

Question 3.

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

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

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

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

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

Solution:

Clearly, from the given graph, we have

(i) Number of books sold in the year

1989 : 170 (approx.)

1990 : 475 (approx.)

1992 : 225 (approx.)

(ii) In the year 1990, about 475 books were sold. In the year 1992, about 225 books were sold.

(iii) Fewer than 250 books were sold in the years 1989 and 1992.

(iv) It can be estimated using the height of the bar such that height of 1 cm = 100 books.

Question 4.

Following table shows the points of each player scored in four games:

(i) Find the mean to determine A’s average number of points scored per game.

Solution:

A’s average number of points scored per game

[latex]\frac {14+16+10+10}{4}[/latex] = [latex]\frac {50}{4}[/latex] = 12.5

(ii) To find the mean number of points per game for C, would you divide the total points by 3 or by 4 ? Why ?

Solution:

C’s average points per game will be found by dividing the sum by 3. It is because he has not played. We cannot say anything about his points in that game.

The required average

= [latex]\frac {8+11+13}{3}[/latex] = [latex]\frac {32}{3}[/latex] = 10[latex]\frac {2}{3}[/latex]

(iii) B played in all the four games. How would you find the mean ?.

Solution:

B’s average points per game

= [latex]\frac {0+8+6+4}{4}[/latex] = [latex]\frac {18}{4}[/latex] = 4.5

(To find B’s average, we find the sum of all observations and divide this by the number of observations 4.)

(iv) Who is the best performer ?

Solution:

Since 12.5 > 8 > 4.5, so the best performer is A.

Question 5.

The marks (out of 100) obtained by a group of students in a science test are 85, 76,90,85,39,48,56,95,81 and 75. Find the:

(i) Highest and the lowest marks obtained by the students.

(ii) Range of the marks obtained.

(iii) Mean marks obtained by the group.

Solution:

Arranging the marks obtained by the group of students in the ascending order, we have :

39, 48, 56, 75, 76, 81, 85, 85, 90 and 95.

(i) Highest and the lowest marks obtained are 95 and 39, respectively.

(ii) Range of the marks obtained

= 95 - 39 = 56.

(iii) Mean marks

= [latex]\frac {39+48+56+75+76+81}{+85+85+90+95}[/latex]

= [latex]\frac {730}{10}[/latex] = 73