#### Term 3 - Probability Complete Study Material

9th Standard

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Maths

Time : 02:00:00 Hrs
Total Marks : 55
10 x 1 = 10
1. A number between 0 and 1 that is used to measure uncertainty is called

(a)

Random variable

(b)

Trial

(c)

Simple event

(d)

Probability

2. Probability lies between

(a)

−1 and +1

(b)

0 and 1

(c)

0 and n

(d)

0 and $\infty$

3. The probability based on the concept of relative frequency theory is called

(a)

Empirical probability

(b)

Classical probability

(c)

Both (1) and (2)

(d)

Neither (1) nor (2)

4. The probability of an event cannot be

(a)

Equal to zero

(b)

Greater than zero

(c)

Equal to one

(d)

Less than zero

5. A random experiment contains

(a)

Atleast one outcome

(b)

At least two outcomes

(c)

Atmost one outcome

(d)

Atmost two outcomes

6. The probability of all possible outcomes of a random experiment is always equal to

(a)

One

(b)

Zero

(c)

Infinity

(d)

All of the above

7. Which of the following cannot be taken as probability of an event?

(a)

0

(b)

0.5

(c)

1

(d)

-1

8. A particular result of an experiment is called

(a)

Trial

(b)

Simple event

(c)

Compound event

(d)

Outcome

9. The six faces of the dice are called equally likely if the dice is

(a)

Small

(b)

Fair

(c)

Six-faced

(d)

Round

10. A letter is chosen at random from the word “STATISTICS”. The probability of getting a vowel is

(a)

$\frac { 1 }{ 10 }$

(b)

$\frac { 2 }{ 10 }$

(c)

$\frac { 3 }{ 10 }$

(d)

$\frac { 4 }{ 10 }$

11. 15 x 2 = 30
12. 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?

13. What is the probability of drawing a King or a Queen or a Jack from a deck of cards?

14. What is the probability of throwing an even number with a single standard dice of six faces?

15. 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?

16. When two coins are tossed, what is the probability that two heads are obtained?

17. Two dice are rolled, find the probability that the sum is
(i) equal to 1
(ii) equal to 4
(iii) less than 13

18. 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.

19. 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.

20. What is the probability that the spinner will not land on a multiple of 3?

21. Frame two problems in calculating probability, based on the spinner shown here.

22. A company manufactures 10000 Laptops in 6 months. In that 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.

23. 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.

24. The probability of guessing the correct answer to a certain question is $\frac { x }{ 3 }$. If the probability of not guessing the correct answer is $\frac { x }{ 5 }$, then find the value of x.

25. If a probability of a player winning a particular tennis match is 0.72. What is the probability of the player loosing the match?

26. 1500 families were surveyed and following data was recorded about their maids at homes

 Type of maids Only part time Only full time Both Number of families 860 370 250

A family is selected at random. Find the probability that the family selected has
(i) Both types of maids
(ii) Part time maids
(iii) No maids

27. 5 x 3 = 15
28. When a dice is rolled, find the probability to get the number greater than 4?

29. In an office, where 42 staff members work, 7 staff members use cars, 20 staff members use two-wheelers and the remaining 15 staff members use cycles. Find the relative frequencies.

30. Team I and Team II play 10 cricket matches each of 20 overs. Their total scores in each match are tabulated in the table as follows:

 Match numbers 1 2 3 4 5 6 7 8 9 10 Team I 200 122 111 88 156 184 99 199 121 156 Team II 143 123 156 92 164 72 100 201 98 157

What is the relative frequency of Team I winning?

31. The probability that it will rain tomorrow is $\\ \frac { 91 }{ 100 }$. What is the probability that it will not rain tomorrow?

32. In a recent year, of the 1184 centum scorers in various subjects in tenth standard public exams, 233 were in mathematics. 125 in social science and 106 in science. If one of the student is selected at random, find the probability of that selected student,
(i) is a centum scorer in Mathematics
(ii) is not a centum scorer in Science