Samacheer Kalvi Class 9 Maths Chapter 9 Probability Solutions
Welcome to NCTB Solutions. Here with this post we are going to help 9th class students by providing Solutions for Samacheer Kalvi Class 9 Maths chapter 9 Probability. Here students can easily find all the solutions for Probability Exercise 9.1, 9.2 and 9.3. Also here our Expert Maths Teacher’s solved all the problems with easily understandable methods with proper guidance so that all the students can understand easily. Here in this post students will get chapter 9 solutions. Here all the solutions are based on Tamil Nadu State Board latest syllabus.
Statistics Exercise 9.1 Solutions :
(1) You are walking along a street. If you just choose a stranger crossing you, what is the probability that his next birthday will fall on a Sunday?
Solution :
Days in a week = 7
So, n (s) = 7
Event only 1 day in week n (A) = 1
∴ Probability,
= n (A)/n (S)
= 1/7
Thus, the probability that his next birthday will fall on a Sunday is 1/7
(2) What is the probability of drawing a King or a Queen or a Jack from a deck of cards?
Solution :
As we all know that,
Number of king card in deck of cards = 4
Number of queen card in deck of cards = 4
Number of jack card in deck of cards = 4
Total card no = 52
∴ The probability a king card = 4/52
∴ The probability a queen card = 4/52
∴ The probability a jack card = 4/52
(3) What is the probability of throwing an even number with a single standard dice of six faces?
Solution :
There are six face in a dice
So n(s) = 6
And we throwing even numbers only
So n(A) = 3
∴ The probability of throwing even number
= 3/6
(4) There are 24 balls in a pot. If 3 of them are Red, 5 of them are Blue and the remaining are Green then, what is the probability of picking out (i) a Blue ball, (ii) a Red ball and (iii) a Green ball?
Solution :
Total ball = 24 n(s) = 24
Number of red ball = 3
Numkber of blue ball = 5
So no of green ball = 24 – (3 + 5) = 16
∴ Probability of red ball = 3/24
∴ Probability of blue Ball = 5/24
∴ Probability of green ball = 16/24
(5) When two coins are tossed, what is the probability that two heads are obtained?
Solution :
If two coins are tossed then n(S) = 4
If two reads are to be obtained
So, n(A) = 2
Therefore, the probability of getting two heads is = 2/4.
(6) Two dice are rolled, find the probability that the sum is
(i) equal to 1
(ii) equal to 4
(iii) less than 13
Solution :
If two dice are rolled
Then n(S) = 36
If two dice are rolled then there nothing that we get sum equal 1.
So n(A) = 0
∴ Probability of get sum of 1,
= 0/36
= 0
If the sum equal to 4
Then n(A) = 3
∴ Probability = 3/36
If the sum equal to less than 13
Then n(A) = 36
Because the maximum number in dice is six and they rolled the maximum time we get 6 + 6 = 12
Then all are less than 13
∴ Probability of getting sum equal to less than 13 is
= 36/36
= 1
(7) A manufacturer tested 7000 LED lights at random and found that 25 of them were defective. If a LED light is selected at random, what is the probability that the selected LED light is a defective one.
Solution :
Total number of light N(S) = 7000
And defective lights n(A) = 25
Then the probability of selected LED light is a defective one is = 25/7000
(8) In a football match, a goalkeeper of a team can stop the goal, 32 times out of 40 attempts tried by a team. Find the probability that the opponent team can convert the attempt into a goal.
Solution :
Number of attempts = 40
Since one team attempts 32 time in 40
Then the other team attempts,
= (40 – 32)
= 8 times
(9) What is the probability that the spinner will not land on a multiple of 3?
Solution :
Total number of gaps = 8
N(S) = 8
If the spinner not land on multiple pf 3
Then n(A) = 6
∴ The probability of the spinner not land on multiple of 3 is 6/8
Statistics Exercise 9.2 Solutions :
(1) A company manufactures 10000 Laptops in 6 months. Out of which 25 of them are found to be defective. When you choose one Laptop from the manufactured, what is the probability that selected Laptop is a good one.
Solution :
N(S) = 10,000
Number of defective laptops = 5
Number of good laptops
= 10000 – 25
= 9975
Probability of good laptop = 9975/10000
(2) In a survey of 400 youngsters aged 16-20 years, it was found that 191 have their voter ID card. If a youngster is selected at random, find the probability that the youngster does not have their voter ID card.
Solution :
N(S) = 400
Total no of youngsters have voter id = 191
No of youngsters does not have voter id
= 400-191
= 209
∴ Probability = 209/400
(3) The probability of guessing the correct answer to a certain question is x/3. if the probability of not guessing the correct answer is x/5, then find the value of x
Solution :
Probability of guessing correct answer = x/3
Probability of not guessing correct answer = x/5
So, x/3 + x/5 = 1
= 5x + 3x/15 = 1
= x = 15/8
Hence, the value of x is 15/8
(4) If a probability of a player winning a particular tennis match is 0.72. What is the probability of the player loosing the match?
Solution :
There are two player in tennis match
So, if probability of a player wining a particular tennis match is 0.72
Therefore, The probability of player loosing the match,
= 1 – 0.72
= 0.28
Statistics Exercise 9.3 Solutions :
Multiple choice questions :
(1) A number between 0 and 1 that is used to measure uncertainty is called
(1) Random variable
(2) Trial
(3) Simple event
(4) Probability
Solution :
Correct option – (4)
A number between 0 and 1 that is used to measure uncertainty is called Probability.
(2) Probability lies between
(1) −1 and +1
(2) 0 and 1
(3) 0 and n
(4) 0 and ∞
Solution :
Correct option – (2)
Probability lies between 0 and 1.
(3) The probability based on the concept of relative frequency theory is called
(1) Empirical probability
(2) Classical probability
(3) Both (1) and (2)
(4) Neither (1) nor (2)
Solution :
Correct option – (1)
The probability based on the concept of relative frequency theory is called Empirical probability.
(4) The probability of an event cannot be
(1) Equal to zero
(2) Greater than zero
(3) Equal to one
(4) Less than zero
Solution :
Correct option – (4)
The probability of an event cannot be less than zero.
(5) The probability of all possible outcomes of a random experiment is always equal to
(1) One
(2) Zero
(3) Infinity
(4) Less than one
Solution :
Correct option – (1)
The probability of all possible outcomes of a random experiment is always equal to One.
(6) If A is any event in S and its complement is A’ then, P(A)′ is equal to
(1) 1
(2) 0
(3) 1−A
(4) 1−P(A)
Solution :
Correct option – (4)
If A is any event in S and its complement is A’ then, P(A)′ is equal to 1−P (A).
(7) Which of the following cannot be taken as probability of an event?
(1) 0
(2) 0.5
(3) 1
(4) −1
Solution :
Correct option – (4)
-1 cannot be taken as probability of an event.
(8) A particular result of an experiment is called
(1) Trial
(2) Simple event
(3) Compound event
(4) Outcome
Solution :
Correct option – (4)
A particular result of an experiment is called Outcome.
(9) A collection of one or more outcomes of an experiment is called
(1) Event
(2) Outcome
(3) Sample point
(4) None of the above
Solution :
Correct option – (1)
A collection of one or more outcomes of an experiment is called Event.
(10) The six faces of the dice are called equally likely if the dice is
(1) Small
(2) Fair
(3) Six-faced
(4) Round
Solution :
Correct option – (2)
The six faces of the dice are called equally likely if the dice is Fair.
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