CBSE Class 9 Mathematics Probability Worksheet Set B

Question. The given table shows the ages (in years) of 360 patients, getting medical treatment in a hospital.

One of the patients is selected at random. The probability that the selected patient’s age is 30 years or more but less than 40 years, is
(a) 1/6
(b) 2/9
(c) 0
(d) 1
Answer : A

Question. The following data shows the relation between the number of families and number of children they have. What is the probability of a family chosen at random having at least two children?

(a) 33/53
(b) 35/53
(c) 34/53
(d) 19/53
Answer : C

Question. If 10/100, 13/100, 15/100, 18/100, x/100, 30/100 are the probabilities of 6 observations of an experiment, then find the value of x.
(a) 12
(b) 13
(c) 14
(d) 15
Answer : C

Question. In a one day match, a player played 40 balls. The runs scored are as follows :

Find the probability that player hits a four or a six.
(a) 3/20
(b) 1/2
(c) 1/4
(d) 9/20
Answer : A

Question. 100 plants each were sown in six different colonies A, B, C, D, E and F. After 31 days, the number of plants survived are as follows:

Find the probability that more than 80 plants survived in a colony?
(a) 2/3
(b) 1/3
(c) 5/6
(d) 1/6
Answer : A

Question. The given table shows the number of students participating in various activities in a school.

One student is chosen at random. Find the probability that the student participates in games.
(a) 3/10
(b) 1/2
(c) 1/7
(d) 1/10
Answer : A

Question. On a particular day, the number of vehicles passing through a crossing is given below:

A particular vehicle is chosen at random. What is the probability that it is not a four-wheeler?
(a) 21/80
(b) 21/40
(c) 3/4
(d) 5/4
Answer : B

Question. Two sections of class IX having 27 students in each section appeared for Mathematics olympiad. The marks obtained by them are shown below.
46, 31, 74, 68, 42, 54, 14, 61, 48, 37, 26, 8, 64, 57,
93, 72, 53, 59, 38, 16, 88, 56, 46, 66, 45, 61, 54, 27,
27, 44, 63, 58, 43, 81, 64, 36, 49, 50, 76, 38, 47, 77,
62, 53, 40, 71, 60, 45, 42, 34, 46, 40, 59, 42
One student is selected at random. Find the probability that selected student is having marks more than 49.
(a) 1/3
(b) 1/2
(c) 1/4
(d) 7/9
Answer : B

Case Based MCQs

Case I : Read the following passage and answer the questions from 46 to 50.
On one day in school, teacher performed an activity with the students. She tells every student to write their weights on their notebook. After that she makes the following frequency distribution table from the collected data and asks some questions

1. Find the probability of a randomly chosen student of weight atleast 50 kg.
(a) 11/50
(b) 13/50
(c) 21/50
(d) 7/50
Answer : A

2. The probability that the selected student has atmost 65 kg weight is
(a) 0
(b) 23/41
(c) 16/17
(d) 1
Answer : D

3. The probability that the weight of the student is not more than or equal to 45 kg is
(a) 15/31
(b) 1/2
(c) 27/50
(d) 2/3
Answer : C

4. The probability that weight of student is less than 60 kg but more than or equal to 45 kg is
(a) 23/50
(b) 13/50
(c) 11/50
(d) 19/50
Answer : D

5. If an experiment is performed, then the probability of an event (E) is
(a) P(E) = No. of trials in which the event has happened/Total no. of trials
(b) P(E) = Total no. of trials/No. of trials in which the event has happened
(c) P(E) = No. of trials in which the event has not happened/Total no. of trials
(d) none of these
Answer : A

Case II : Read the following passage and answer the questions from 51 to 55.
In a factory, the workers are paid on daily basis. The new manager wants to know the salary slab of the workers and finds the data as given below .

Now, if a worker is chosen at random, then :

1. Probability that the worker is getting atmost ₹ 500 is
(a) 3/80
(b) 9/80
(c) 1/80
(d) 4/25
Answer : B

2. Probability that the worker is getting atleast ₹ 701 is
(a) 23/80
(b) 43/80
(c) 41/80
(d) 61/80
Answer : B

3. Probability that the worker is getting ₹ 901 - ₹ 1100 is
(a) 3/40
(b) 1/40
(c) 9/40
(d) 2/23
Answer : C

4. Probability that the worker is getting atmost ₹ 900 is
(a) 7/40
(b) 3/31
(c) 31/40
(d) 4/31
Answer : C

5. Probability that the worker is getting less than ₹ 300 is
(a) 0
(b) 1
(c) 1/2
(d) 2/3
Answer : A

Assertion & Reasoning Based MCQs

Directions (Q.56 to 60) : In these questions, a statement of Assertion is followed by a statement of Reason is given.
Choose the correct answer out of the following choices :
(a) Assertion and Reason both are correct statements and Reason is the correct explanation of Assertion.
(b) Assertion and Reason both are correct statements but Reason is not the correct explanation of Assertion.
(c) Assertion is correct statement but Reason is wrong statement.
(d) Assertion is wrong statement but Reason is correct statement.

1. Assertion : A coin is tossed 30 times and head appears 18 times. Then the probability of getting a tail is 12/30 .
Reason : Probability of happening of an event
= Number of trials in which the event happened/Total number of trials.
Answer : A

2. Assertion : A die is thrown, if probability of getting an even number is 1/2, then the probability of getting an odd number is also 1/2 .
Reason : P(E₁) + P(E₂) + P(E₃) + ... + P(E_n) = 1, where E₁, E₂, E₃, ..., E_n are n elementary eventsassociated to a random experiment.
Answer : A

3. Assertion : Three coins are tossed. Numberof elements in the sample space is 8.
Reason : When a coin is tossed n times,then the number of elements in its sample spaceis 2n.
Answer : A

4 Assertion : In a survey of 365 studentsaged 13-14 years, it was found that 130 likedto opt French as third language. If a studentselected at random, then the probability that he/she does not like to opt French as third languageis 47/73.
Reason : The probability of an event
E = Number of trials in which E is not happened/Total number of trials
Answer : C

5. Assertion : In a class of 45 students, 39 passed an examination. If a student is selected at random, then the probability that the student has not passed the examination is 13/15
Reason : P(E) + P(not E) = 1
Answer : D

Please refer to attached file for CBSE Class 9 Mathematics Worksheet - Probability