# Selina solutions for Concise Mathematics Class 7 ICSE chapter 21 - Data Handling [Latest edition]

#### Chapters ## Chapter 21: Data Handling

Exercise 21 (A)Exercise 21 (B)
Exercise 21 (A)

### Selina solutions for Concise Mathematics Class 7 ICSE Chapter 21 Data Handling Exercise 21 (A)

Exercise 21 (A) | Q 1.1

Consider the following numbers:
68, 76, 63, 75, 93, 83, 70, 115, 82, 105, 90, 103, 92, 52, 99, 73, 75, 63, 77 and 71.
Arrange these numbers in ascending order.

Exercise 21 (A) | Q 1.2

Consider the following numbers:
68, 76, 63, 75, 93, 83, 70, 115, 82, 105, 90, 103, 92, 52, 99, 73, 75, 63, 77 and 71.
What the range of these numbers?

Exercise 21 (A) | Q 2

Represent the following data in the form of a frequency distribution table:
16, 17, 21, 20, 16, 20, 16, 18, 17, 21, 17, 18, 19, 17, 15, 15, 19, 19, 18, 17, 17, 15, 15, 16, 17, 17, 19, 18, 17, 16, 15, 20, 16, 17, 19, 18, 19, 16, 21 and 17.

Exercise 21 (A) | Q 3

A die was thrown 20 times and the following scores were recorded.
2, 1, 5, 2, 4, 3, 6, 1, 4, 2, 5, 1, 6, 2, 6, 3, 5, 4, 1 and 3.
Prepare a frequency table for the scores.

Exercise 21 (A) | Q 4

Following data shows the weekly wages (in ₹) of 10 workers in a factory.
3500, 4250, 4000, 4250, 4000, 3750, 4750, 4000, 4250 and 4000
(i) Prepare a frequency distribution table.
(ii) What is the range of wages (in ₹)?
(iii) How many workers are getting maximum wages?

Exercise 21 (A) | Q 5

The marks obtained by 40 students of a class are given below:
80, 10, 30, 70, 60, 50, 50, 40, 40, 20, 40, 90, 50, 30, 70, 10, 60, 50, 20, 70, 70, 30, 80, 40,20, 80, 90, 50, 80, 60, 70, 40, 50, 60, 90, 60, 40, 40, 60 and 60
(i) Construct a frequency distribution table.
(ii) Find how many students have marks equal to or more than 70?
(iii) How many students obtained marks below 40?

Exercise 21 (A) | Q 6.1

Arrange the following data in descending order:
3.3, 3.2, 3.1, 3.7, 3.6, 4.0, 3.5, 3.9, 3.8, 4.1, 3.5, 3.8, 3.7, 3.9 and 3.4. Determine the range.

Exercise 21 (A) | Q 6.2

Arrange the following data in descending order:
3.3, 3.2, 3.1, 3.7, 3.6, 4.0, 3.5, 3.9, 3.8, 4.1, 3.5, 3.8, 3.7, 3.9 and 3.4.
How many numbers are less than 3.5?

Exercise 21 (A) | Q 6.3

Arrange the following data in descending order:
3.3, 3.2, 3.1, 3.7, 3.6, 4.0, 3.5, 3.9, 3.8, 4.1, 3.5, 3.8, 3.7, 3.9 and 3.4.
How many numbers are 3.8 or above?

Exercise 21 (B)

### Selina solutions for Concise Mathematics Class 7 ICSE Chapter 21 Data Handling Exercise 21 (B)

Exercise 21 (B) | Q 1

Find the mean of 53, 61, 60, 67 and 64.

Exercise 21 (B) | Q 2

Find the mean of first six natural numbers.

Exercise 21 (B) | Q 3

Find the mean of first ten odd natural numbers.

Exercise 21 (B) | Q 4

Find the mean of all factors of 10.

Exercise 21 (B) | Q 5

Find the mean of x + 3, x + 5, x + 7, x + 9 and x + 11.

Exercise 21 (B) | Q 6

If different values of variable x are 19.8, 15.4, 13.7, 11.71, 11.8, 12.6, 12.8, 18.6, 20.5 and 2.1, find the mean.

Exercise 21 (B) | Q 7.1

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, increased by 3

Exercise 21 (B) | Q 7.2

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, decreased by 7

Exercise 21 (B) | Q 7.3

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, multiplied by 2

Exercise 21 (B) | Q 7.4

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, divided by 0.5

Exercise 21 (B) | Q 7.5

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, increased by 60%

Exercise 21 (B) | Q 7.6

The mean of a certain number of observations is 32. Find the resulting mean, if the observation is, decreased by 20%

Exercise 21 (B) | Q 8

The pocket expenses (per day) of Anuj, during a certain week, from Monday to Saturday were ₹85.40, ₹88.00, ₹86.50, ₹84.75, ₹82.60 and ₹87.25. Find the mean pocket expenses per day.

Exercise 21 (B) | Q 9

If the mean of 8, 10, 7, x + 2 and 6 is 9, find the value of x.

Exercise 21 (B) | Q 10

Find the mean of first six multiples of 3.

Exercise 21 (B) | Q 11

Find the mean of first five prime numbers.

Exercise 21 (B) | Q 12

The mean of six numbers: x − 5, x − 1, x, x + 2, x + 4 and x + 12 is 15. Find the mean of first four numbers.

Exercise 21 (B) | Q 13

Find the mean of squares of first five whole numbers.

Exercise 21 (B) | Q 14

If the mean of 6, 4, 7, p and 10 is 8, find the value of p.

Exercise 21 (B) | Q 15

Find the mean of the first six multiples of 5.

Exercise 21 (B) | Q 16

The rainfall (in mm) in a city on 7 days of a certain week is recorded as follows

 Day: Mon Tue Wed Thus Fri Sat Sun Rainfall (in mm): 0.5 2.7 2.6 0.5 2 5.8 1.5

Find the total and average (mean) rainfall for the week.

Exercise 21 (B) | Q 17

The mean of marks scored by 100 students was found to be 40, later on, it was discovered that a score of 53 was misread as 83. Find the correct mean.

Exercise 21 (B) | Q 18

The mean of five numbers is 27. If one number is excluded, the mean of the remaining numbers is 25. Find the excluded number.

Exercise 21 (B) | Q 19

The mean of 5 numbers is 27. If one new number is included, the new mean is 25. Find the included number.

Exercise 21 (B) | Q 20

Mean of 5 numbers is 20 and the mean of the other 5 numbers is 30. Find the mean of all the 10 numbers taken together.

Exercise 21 (B) | Q 21.1

Find the median of 5, 7, 9, 11, 15, 17, 2, 23 and 19.

Exercise 21 (B) | Q 21.2

Find the median of 9, 3, 20, 13, 0, 7 and 10

Exercise 21 (B) | Q 21.3

Find the median of 18, 19, 20, 23, 22, 20, 17, 19, 25 and 21

Exercise 21 (B) | Q 21.4

Find the median of 3.6, 9.4, 3.8, 5.6, 6.5, 8.9, 2.7, 10.8, 15.6, 1.9 and 7.6.

Exercise 21 (B) | Q 22

Find the mean and the mode for the following data:

 Term 18 22 23 30 34 38 Frequency 3 5 10 2 8 2
Exercise 21 (B) | Q 23.1

Find the mode of 5, 6, 9, 13, 6, 5, 6, 7, 6, 6, 3

Exercise 21 (B) | Q 23.2

Find the mode of 7, 7, 8, 10, 10, 11, 10, 13, 14

Exercise 21 (B) | Q 24.1

Find the mode of:

 x 15 16 17 18 19 20 21 22 23 f 6 7 9 13 10 12 8 0 4
Exercise 21 (B) | Q 24.2

Find the mode of:

 Height (cm) 37 38 39 40 41 Number of plants 46 89 93 90 153
Exercise 21 (B) | Q 25

The heights (in cm) of 8 girls of a class are 140, 142, 135, 133, 137, 150, 148 and 138 respectively. Find the mean height of these girls and their median height.

Exercise 21 (B) | Q 26.1

Find the mean, the median, and the mode of 12, 24, 24, 12, 30 and 12.

Exercise 21 (B) | Q 26.2

Find the mean, the median, and the mode of 21, 24, 21, 6, 15, 18, 21, 45, 9, 6, 27 and 15.

Exercise 21 (B) | Q 27

The following table shows the market positions of some brands of soap.
Draw a suitable bar graph:

 Soap (brands): A B C D E No. of buyers: 51 27 15 24 18
Exercise 21 (B) | Q 28

The birth rate per thousand of different countries over a particular period of time is shown below.

 INDIA U.K. CHINA GERMANY SWEDEN 35 22 43 13 8

## Chapter 21: Data Handling

Exercise 21 (A)Exercise 21 (B) ## Selina solutions for Concise Mathematics Class 7 ICSE chapter 21 - Data Handling

Selina solutions for Concise Mathematics Class 7 ICSE chapter 21 (Data Handling) include all questions with solution and detail explanation. This will clear students doubts about any question and improve application skills while preparing for board exams. The detailed, step-by-step solutions will help you understand the concepts better and clear your confusions, if any. Shaalaa.com has the CISCE Concise Mathematics Class 7 ICSE solutions in a manner that help students grasp basic concepts better and faster.

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Concepts covered in Concise Mathematics Class 7 ICSE chapter 21 Data Handling are Concept for Collection and Organisation of Data – Choosing the Data to Collect for a Hypothesis Testing, Concept for Constructing, Interpretation of Bar Graphs, Concept of Mode, Concept of Data Handling, Concept of Median.

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