EduSahara™ Worksheet

Question 1

1.

There are 70 students in a class room of whom 30 are boys and 40 are girls. From these students, one is choosen at random. What is the probability that the choosen student is a boy ?

(i)

4
7
(ii)

3
7
(iii)

1
2
(iv)

2
7

Question 2

2.

Which of the following are possible values of probability?

a)

-4.4

b)

0.17

c)

3

d)

9

5

e)

1

2

(i)

{a,b}
(ii)

{b,e}
(iii)

{c,e}
(iv)

{c,e,b}
(v)

{d,a,b}

Question 3

3.

Which of the following are true?

a)

P(E) - P(not E) = 0

b)

P(E) = 1 - P(
E
)

c)

P(E) + P(
E
) = 0

d)

P(E) + P(not E) = 1

e)

P(E) - P(
E
) = 0

(i)

{c,d,b}
(ii)

{a,b}
(iii)

{b,d}
(iv)

{e,a,b}
(v)

{c,d}

Question 4

4.

In a lottery, there are 26 prizes and 10 blanks. What is the probability of not getting a prize?

(i)

6
19
(ii)

13
18
(iii)

2
9
(iv)

1
3
(v)

5
18

Question 5

5.

The following table shows the blood-groups of 387 students of a class.

Blood group

A

O

AB

B

Number of students

72

81

108

126

One student of the class is choosen at random. What is the probability that the choosen student has blood group 'A' ?

(i)

9
43
(ii)

7
43
(iii)

8
43
(iv)

9
44
(v)

35
43

Question 6

6.

Which of the following are true?

a)	The probability of an unsure event is 0
b)	The probability of a sure event is 1
c)	For an event E, we have 0 ≤ P(E) ≤ 1
d)	The probability of an imposible event can be > 1
e)	The probability of an impossible event is 1

(i)

{a,b}
(ii)

{b,c}
(iii)

{d,c,b}
(iv)

{e,a,b}
(v)

{d,c}

Question 7

7.

In a lottery, there are 30 prizes and 13 blanks. What is the probability of getting a prize?

(i)

29
43
(ii)

31
44
(iii)

30
43
(iv)

13
43
(v)

31
43

Question 8

8.

There are 62 students in a class room of whom 26 are boys and 36 are girls. From these students, one is choosen at random. What is the probability that the choosen student is a girl ?

(i)

13
31
(ii)

19
31
(iii)

17
31
(iv)

18
31
(v)

19
32

Question 9

9.

In a lottery, there are 29 prizes and 15 blanks. What is the probability of not getting a prize?

(i)

29
44
(ii)

4
11
(iii)

15
44
(iv)

7
22
(v)

16
45

Question 10

10.

A die is thrown 600 times. The number 2 appears on the upper face 66 times. Now the die is thrown at random. What is the probability of getting a 2 ?

(i)

12
101
(ii)

89
100
(iii)

11
100
(iv)

3
25
(v)

1
10

Question 11

11.

Three coins are tossed simultaneously 235 times with the following frequencies of different outcomes :

Outcome

3 heads

2 heads

1 heads

No heads

Frequency

30

55

70

80

If the three coins are simultaneously tossed again, compute the probability of '1 heads' coming up.

(i)

15
47
(ii)

5
16
(iii)

14
47
(iv)

13
47
(v)

33
47

Question 12

12.

A survey of 130 men showed that only 40 of them know French. Out of these men, if one is selected at random, what is the probability that the selected man knows French?

(i)

5
14
(ii)

4
13
(iii)

5
13
(iv)

3
13
(v)

9
13

Question 13

13.

The distances (in km) of engineers from their residence to their place of work were found as follows

26

16

18

22

14

21

23

14

19

8

9

What is the empirical probability that an engineer lives greater than 14 km from her place of work?

(i)

4
11
(ii)

8
11
(iii)

7
11
(iv)

6
11
(v)

2
3

Question 14

14.

Two players Renuka and Swetha play a tennis match. It is known that the probability of Renuka winning the match is 0.50. What is the probability of Swetha winning the match?

(i)

1
2
(ii)

3
4
(iii)

4
5
(iv)

2
3
(v)

5
6

Question 15

15.

The distances (in km) of engineers from their residence to their place of work were found as follows

10

23

27

7

10

19

26

12

13

23

8

What is the empirical probability that an engineer lives less than 8 km from her place of work?

(i)

1
11
(ii)

1
6
(iii)

2
11
(iv)

0
(v)

10
11

Question 16

16.

On a particular day, at a crossing in a city, the various types of 125 vehicles going past during a time-interval were observed as under:

Type of Vehicle

Three-wheeler

Four-wheeler

Two-wheeler

Frequency

35

40

50

Out of these vehicles, if one is choosen at random, what is the probability that the choosen vehicle is a 'Two-wheeler' ?

(i)

2
5
(ii)

1
5
(iii)

1
2
(iv)

3
5

Question 17

17.

If P(E) =
0.8
, find P(
E
)

(i)

0.2
(ii)

2.2
(iii)

8.2
(iv)

1.2
(v)

7.2

Question 18

18.

A die is thrown 140 times. Prime numbers appeared on the upper face 125 times. If a die is thrown at random, what is the probability of getting a prime number?

(i)

25
28
(ii)

3
28
(iii)

6
7
(iv)

26
29
(v)

13
14

Question 19

19.

A coin is tossed 80 times and tail appears 60 times. If the coin is tossed again, what is the probability of getting a head?

(i)

2
5
(ii)

1
2
(iii)

0
(iv)

3
4
(v)

1
4

Question 20

20.

Two coins are tossed simultaneously 150 times and it was observed that both heads appeared 30 times. If two coins are tossed simultaneously at random, what is the probability of getting both heads?

(i)

1
3
(ii)

1
5
(iii)

2
5
(iv)

4
5
(v)

0

Question 21

21.

Which of the following experiments have equally likely outcomes?

a)	A ball is hit. It reaches the boundary or not
b)	A baby is born. It is a boy or girl
c)	A man starts his vehicle. It starts or it does not starts
d)	A true/false question is attempted. The answer is either right or wrong
e)	A man throws a die. The number on the top is either 2 or not 2

(i)

{e,a,b}
(ii)

{c,d,b}
(iii)

{b,d}
(iv)

{a,b}
(v)

{c,d}

Question 22

22.

207 families with 2 children were selected randomly, and the following data were recorded

No. of girls in a family

0

1

2

Number of families

45

72

90

Compute the probability of the family, chosen at random, having 1 girl.

(i)

15
23
(ii)

8
23
(iii)

9
23
(iv)

7
23
(v)

3
8

Question 23

23.

Two coins are tossed simultaneously 60 times and it was observed that both tails appeared 40 times. If two coins are tossed simultaneously at random, what is the probability of getting both tails?

(i)

1
(ii)

2
3
(iii)

3
4
(iv)

1
3

Question 24

24.

A coin is tossed 50 times and head appears 25 times. If the coin is tossed again, what is the probability of getting a tail?

(i)

3
4
(ii)

2
3
(iii)

1
2
(iv)

5
6
(v)

4
5

Question 25

25.

A die is thrown 395 times with the frequencies for outcomes 1, 2, 3, 4, 5 and 6 as given in the following table

Outcome

1

2

3

4

5

6

Frequency

25

30

50

70

105

115

If the die is thrown again randomly, find the probability of getting 4 as outcome.

(i)

65
79
(ii)

3
16
(iii)

14
79
(iv)

15
79
(v)

13
79

Assignment Key