NCERT Solutions for Class 10 विज्ञान Chapter 15 Probability

Probability Here is the CBSE विज्ञान Chapter 15 for Class 10 students. Summary and detailed explanation of the lesson, including the definitions of difficult words. All of the exercises and questions and answers from the lesson's back end have been completed. NCERT Solutions for Class 10 विज्ञान Probability Chapter 15 NCERT Solutions for Class 10 विज्ञान Probability Chapter 15 The following is a summary in Hindi and English for the academic year 2025-26. You can save these solutions to your computer or use the Class 10 विज्ञान.

Question 1

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A survey was conducted by a group of students as a part of their environment awareness programme, in which they collected the following data regarding the number of plants in 20 houses in a locality. Find the mean number of plants per house.

Number of plants

Number of houses

0-2

1

2-4

2

4-6

1

6-8

5

8-10

6

10-12

2

12-14

3

Which method did you use for finding the mean and why?

Solution

Number of plants	Number of houses (f_i)	Class mark (x_i)	f_ix_i
0-2	1	1	1
2-4	2	3	6
4-6	1	5	5
6-8	5	7	35
8-10	6	9	54
10-12	2	11	22
12-14	3	13	39
Total	Σf_i = 20		Σf_ix_i = 162

Here, we have

sum from blank to blank of straight f subscript straight i equals 20 comma space sum from blank to blank of straight f subscript straight i straight x subscript straight i

= 162
Now,

top enclose straight x equals fraction numerator begin display style sum from blank to blank of end style f subscript i x subscript i over denominator begin display style sum from blank to blank of end style f subscript i end fraction equals 162 over 2 equals 8.1

Hence, the mean number of plants per house = 8.1
We have used the direct method for finding the mean because numerical values of x_iand f_i are small.

Sponsor Area

Daily wages (in Rs.)	Number of workers
100-120	12
120-140	14
140-160	8
160-180	6
180-200	10

Daily pocket allowance (in Rs.)	11-13	13-15	15-17	17-19	19-21	21-23	23-25
No. of childrens	7	6	9	13	f	5	4

Number of heart beats per minute	65-68	68-71	71-74	74-77	77-80	80-83	83-86
Number of women	2	4	3	8	7	4	2

No. of Mangoes	50-52	53-55	56-58	59-61	62-64
No. of boxes	15	110	135	115	25

Daily Exp. (in Rs.)	100-150	150-200	200-250	250-300	300-350
No. of house hold	4	5	12	2	2

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NCERT Solutions for Class 10 विज्ञान Chapter 15 Probability

Consider the following distribution of daily wages of 50 workers of a factory:

Daily wages (in Rs.)

Number of workers

100-120

12

120-140

14

140-160

8

160-180

6

180-200

10

Find the mean daily wages of the workers of the factory by using an appropriate method.

The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs. 18. Find the missing frequency 'f'.

Daily pocket allowance (in Rs.)

11-13

13-15

15-17

17-19

19-21

21-23

23-25

No. of childrens

7

6

9

13

f

5

4

The table below shows the daily expenditure on food of 25 household in a locality.

Daily Exp. (in Rs.)

100-150

150-200

200-250

250-300

300-350

No. of house hold

4

5

12

2

2

Find the mean daily expenditure on food by a suitable method.

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

Number of days

0-6

6-10

10-14

14-20

20-28

28-38

38-40

Number of students

11

10

7

4

4

3

1

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.

Literacy rate (in %)

45-55

55-65

65-75

75-85

85-95

Number of cities

3

10

11

8

3

The following table shows the ages of the patients admitted in a hospital during a year.

Find the mode and mean of the data given below. Compare and interpret the measures of central tendency.

Age (in yrs)

No. of patients

5-15

6

15-25

11

25-35

21

35-45

23

45-55

14

55-65

5

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Phone Number

Email Address

Loaction

Number of plants	Number of houses
0-2	1
2-4	2
4-6	1
6-8	5
8-10	6
10-12	2
12-14	3

Concentration of SO₂ (in ppm)	0.00-0.04	0.04-0.08	0.08-012	0.12-0.16	0.16-0.20	0.20-0.24
Frequencey	4	9	9	2	4	2

Number of days	0-6	6-10	10-14	14-20	20-28	28-38	38-40
Number of students	11	10	7	4	4	3	1

Literacy rate (in %)	45-55	55-65	65-75	75-85	85-95
Number of cities	3	10	11	8	3

Age (in yrs)	No. of patients
5-15	6
15-25	11
25-35	21
35-45	23
45-55	14
55-65	5

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NCERT Solutions for Class 10 विज्ञान Chapter 15 Probability

Consider the following distribution of daily wages of 50 workers of a factory: Daily wages (in Rs.) Number of workers 100-120 12 120-140 14 140-160 8 160-180 6 180-200 10 Find the mean daily wages of the workers of the factory by using an appropriate method.

The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs. 18. Find the missing frequency 'f'. Daily pocket allowance (in Rs.) 11-13 13-15 15-17 17-19 19-21 21-23 23-25 No. of childrens 7 6 9 13 f 5 4

The table below shows the daily expenditure on food of 25 household in a locality. Daily Exp. (in Rs.) 100-150 150-200 200-250 250-300 300-350 No. of house hold 4 5 12 2 2 Find the mean daily expenditure on food by a suitable method.

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent. Number of days 0-6 6-10 10-14 14-20 20-28 28-38 38-40 Number of students 11 10 7 4 4 3 1

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate. Literacy rate (in %) 45-55 55-65 65-75 75-85 85-95 Number of cities 3 10 11 8 3

The following table shows the ages of the patients admitted in a hospital during a year. Find the mode and mean of the data given below. Compare and interpret the measures of central tendency. Age (in yrs) No. of patients 5-15 6 15-25 11 25-35 21 35-45 23 45-55 14 55-65 5

Mock Test Series

NCERT Sample Papers

Entrance Exams Preparation

Consider the following distribution of daily wages of 50 workers of a factory:

Daily wages (in Rs.)

Number of workers

100-120

12

120-140

14

140-160

8

160-180

6

180-200

10

Find the mean daily wages of the workers of the factory by using an appropriate method.

The following distribution shows the daily pocket allowance of children of a locality. The mean pocket allowance is Rs. 18. Find the missing frequency 'f'.

Daily pocket allowance (in Rs.)

11-13

13-15

15-17

17-19

19-21

21-23

23-25

No. of childrens

7

6

9

13

f

5

4

The table below shows the daily expenditure on food of 25 household in a locality.

Daily Exp. (in Rs.)

100-150

150-200

200-250

250-300

300-350

No. of house hold

4

5

12

2

2

Find the mean daily expenditure on food by a suitable method.

A class teacher has the following absentee record of 40 students of a class for the whole term. Find the mean number of days a student was absent.

Number of days

0-6

6-10

10-14

14-20

20-28

28-38

38-40

Number of students

11

10

7

4

4

3

1

The following table gives the literacy rate (in percentage) of 35 cities. Find the mean literacy rate.

Literacy rate (in %)

45-55

55-65

65-75

75-85

85-95

Number of cities

3

10

11

8

3

The following table shows the ages of the patients admitted in a hospital during a year.

Find the mode and mean of the data given below. Compare and interpret the measures of central tendency.

Age (in yrs)

No. of patients

5-15

6

15-25

11

25-35

21

35-45

23

45-55

14

55-65

5