In 10th
grade worksheet on probability we will practice
various types of problems based on definition of probability and the theoretical
probability or classical probability.

1. Write down the total number of possible outcomes when the
ball is drawn from a bag containing 5 red balls, 3 black balls and 4 green
balls.

2. Fill in the blanks.

(i) The probability of an event is less than or equal to ……. but greater than or equal to……. .

(ii) If E is an event then P(E) + P(E¯¯¯¯

E¯) =
……. .

(iii) The probability of a sure event is ……. .

(iv) The probability of an impossible event is ……. .

3. A survey was conducted on 1200 families and the number of children in each family was recorded. The results are given below:

No. Of Children

0

1

2

3

4

5

Total

No. of Families

42

446

534

115

52

11

1200

If a family is chosen at random, find the probability that it will have

(i) exactly 2 children

(ii) less than 2 children

(iii) more than 3 children

(iv) no children

4. A survey was conducted on 1500 family having 2 children each. The results obtained are given below:

No. of Girl children

2

1

0

Total

No. of families

475

815

210

1500

If one family is selected at random, find the probability that it will have

(i) no girl child

(ii) at least one girl child

(iii) no boy child

5. Seeds were kept in 5 containers to germinate. Each container contained 100 seeds. After 20 days the germinated seeds were counted and the results were recorded as shown below:

Container Number

1

2

3

4

5

Number of germinated Seeds

83

72

90

76

84

If a container is selected at random from then, find the probability of finding

(i) less than 70 germinated seeds

(ii) more than 72 germinated seeds

(iii) more than 70 germinated seeds

(iv) at least 83 germinated seeds

6. The marks scored by 100 students are given below:

Overlapping Intervals of Marks Scored

0 – 20

20 – 40

40 – 60

60 – 80

80 – 100

Total

Number of Students

8

13

37

32

10

100

Find the probability of s student scoring

(i) less than 20

(ii) below 60 but not below 40

(iii) less than 40

(iv) more than or equal to 60

(v) below 80.

7. A bag contains 8 red marbles and 6 white marbles. A marble
is picked up at random. Find the probability of

(i) getting a red marble

(ii) getting a marble which is not red

8. A box contains 5 red marbles, 7 black marbles and 3 white
marbles. One marble is taken out from the box at random. What is the
probability that the marble taken out will be

(i) black

(ii) red

(iii) not white

(iv) black or white

9. Find the probability that a number selected at random
from the numbers 1, 2, 3, 4, ….., 34, 35 is a

(i) prime number

(ii) multiple of 7

(iii) divisible by 3 and 5

(iv) multiple of 3 or 5

(v) not a multiple of 7.

10. A bag contains 6 red balls, 8 wite balls, 5 green balls
and 3 balls. One ball is drawn at random from the bag. Find the probability
that the ball drawn is

(i) white

(ii) black or red

(iii) not white

(iv) neither white nor black

11. In a lottery there are 5 prizes and 45 blanks. Sophie
has one ticket for the lottery. What is the chance (probability) that Sophie

(i) will get a prize

(ii) will not get a prize?

Also verify that the sum of the probabilities in (i) and (ii)
is 1.

12. A box contains 19 balls bearing numbers from 1 to 19. A
ball is drawn at random from the box. Find the probability that the number on
the ball is

(i) a composite number

(ii) divisible by 3 or 4

(iii) divisible neither by 5 nor by 10

(iv) an even number

13. There are two children in a family. Find the probability
that there is at least one girl in the family.

14. In a class there are 35 boys and 15 girls. What is the
probability of a randomly selected student of the class to be a girl?

15. Find the probability of getting 53 Mondays in a non-leap
year.

16. Find the probability of getting 53 Fridays in a leap
year.

17. Find the probability of getting 52 Saturdays in a leap
year.

18. If the probability of India winning the next Cricket
World Cup is 0.25, what is the probability India not winning the next Cricket
World Cup?

19. In an experiment there are exactly three elementary
events. The probabilities of two of them are 29

29 and 39

39
respectively. What is the probability of the third elementary event?

Note: The sum of all the elementary events is 1.

grade worksheet on probability are given
below to check the exact answers of the questions.

1. 12

2. (i) 1, 0 respectively.

(ii) 1

(iii) 1

(iv) 0

3. (i) 89200

89200

(ii) 61150

61150

(iii) 21400

21400

(iv) 7200

7200

4. (i) 750

750

(ii) 4350

4350

(iii) 1960

1960

5. (i) 0

(ii) 45

45

(iii) 1

(iv) 12

12

6. (i) 225

225

(ii) 37100

37100

(iii) 21100

21100

(iv) 2150

2150

(v) 910

910

7. (i) 47

47

(ii) 37

37

8. (i) 715

715

(ii) 13

13

(iii) 45

45

(iv) 23

23

9. (i) 1135

1135

(ii) 17

17

(iii) 235

235

(iv) 1635

1635

(v) 67

67

Hint: Multiples of 3 or 5 are 3, 6, 9, 12, 15, 18, 21, 24,
27, 30, 33, 5, 10, 20, 25, 35.

10. (i) 411

411

(ii) 922

922

(iii) 711

711

(iv) 12

12

11. (i) 110

110

(ii) 910

910

12. (i) 1019

1019

(ii) 919

919

(iii) 1619

1619

(iv) 919

919

13. 34

34

14. 310

310

15. 17

17

16. 27

27

17. 57

57

18. 34

34

19. 49

49

Hint: The sum of all the elementary events is 1.