EduSahara™ Worksheet

Question 1

1.

Which of the following experiments have equally likely outcomes?

a)	A baby is born. It is a boy or girl
b)	A ball is hit. It reaches the boundary or not
c)	A man throws a die. The number on the top is either 6 or not 6
d)	A man starts his vehicle. It starts or it does not starts
e)	A true/false question is attempted. The answer is either right or wrong

(i)

{a,e}
(ii)

{d,b,a}
(iii)

{b,a}
(iv)

{c,e,a}
(v)

{c,e}

Question 2

2.

Two coins are tossed simultaneously 80 times and it was observed that both tails appeared 50 times. If two coins are tossed simultaneously at random, what is the probability of getting both tails?

(i)

3
4
(ii)

2
3
(iii)

5
8
(iv)

1
2
(v)

3
8

Question 3

3.

There are 66 students in a class room of whom 26 are boys and 40 are girls. From these students, one is choosen at random. What is the probability that the choosen student is a girl ?

(i)

20
33
(ii)

7
11
(iii)

13
33
(iv)

19
33
(v)

21
34

Question 4

4.

Two coins are tossed simultaneously 120 times and it was observed that both heads appeared 25 times. If two coins are tossed simultaneously at random, what is the probability of getting both heads?

(i)

1
4
(ii)

5
24
(iii)

19
24
(iv)

6
25
(v)

1
6

Question 5

5.

In a lottery, there are 23 prizes and 19 blanks. What is the probability of not getting a prize?

(i)

3
7
(ii)

20
43
(iii)

19
42
(iv)

10
21
(v)

23
42

Question 6

6.

A survey of 90 men showed that only 55 of them know Sanskrit. Out of these men, if one is selected at random, what is the probability that the selected man knows Sanskrit?

(i)

7
18
(ii)

2
3
(iii)

11
18
(iv)

12
19
(v)

5
9

Question 7

7.

Two players Vimala and Karishma play a tennis match. It is known that the probability of Vimala winning the match is 0.67. What is the probability of Karishma winning the match?

(i)

33
100
(ii)

17
50
(iii)

67
100
(iv)

8
25
(v)

34
101

Question 8

8.

A coin is tossed 40 times and head appears 20 times. If the coin is tossed again, what is the probability of getting a tail?

(i)

5
6
(ii)

2
3
(iii)

4
5
(iv)

1
2
(v)

3
4

Question 9

9.

243 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

54

81

108

Compute the probability of the family, chosen at random, having no girls.

(i)

1
3
(ii)

1
9
(iii)

7
9
(iv)

3
10
(v)

2
9

Question 10

10.

A coin is tossed 50 times and tail appears 35 times. If the coin is tossed again, what is the probability of getting a head?

(i)

1
5
(ii)

7
10
(iii)

2
5
(iv)

4
11
(v)

3
10

Question 11

11.

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

10

20

7

3

22

29

16

24

12

18

What is the empirical probability that an engineer lives greater than 22 km from her place of work?

(i)

2
5
(ii)

1
3
(iii)

1
5
(iv)

0
(v)

4
5

Question 12

12.

The following table shows the blood-groups of 459 students of a class.

Blood group

B

AB

O

A

Number of students

81

117

126

135

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

(i)

6
17
(ii)

5
17
(iii)

1
3
(iv)

12
17
(v)

4
17

Question 13

13.

Which of the following are possible values of probability?

a)

0.62

b)

3

c)

-4.4

d)

5

4

e)

4

8

(i)

{c,e}
(ii)

{c,e,a}
(iii)

{a,e}
(iv)

{b,a}
(v)

{d,b,a}

Question 14

14.

Which of the following are true?

a)

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

b)

P(E) = 1 - P(
E
)

c)

P(E) - P(
E
) = 0

d)

P(E) + P(
E
) = 0

e)

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

(i)

{a,b}
(ii)

{d,b,a}
(iii)

{d,b}
(iv)

{e,c,a}
(v)

{c,a}

Question 15

15.

Three coins are tossed simultaneously 265 times with the following frequencies of different outcomes :

Outcome

3 heads

2 heads

1 heads

No heads

Frequency

50

60

65

90

If the three coins are simultaneously tossed again, compute the probability of '2 heads' coming up.

(i)

41
53
(ii)

12
53
(iii)

13
53
(iv)

11
53
(v)

13
54

Question 16

16.

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

21

17

1

5

9

20

30

23

4

19

7

25

4

26

What is the empirical probability that an engineer lives less than 1 km from her place of work?

(i)

1
(ii)

3
4
(iii)

1
2
(iv)

1
4
(v)

0

Question 17

17.

There are 58 students in a class room of whom 36 are boys and 22 are girls. From these students, one is choosen at random. What is the probability that the choosen student is a boy ?

(i)

19
30
(ii)

11
29
(iii)

17
29
(iv)

18
29
(v)

19
29

Question 18

18.

A survey of 90 men showed that only 20 of them know Sanskrit. Out of these men, if one is selected at random, what is the probability that the selected man knows Sanskrit?

(i)

7
9
(ii)

1
3
(iii)

2
9
(iv)

3
10
(v)

1
9

Question 19

19.

If P(E) =
0.5
, find P(
E
)

(i)

1.5
(ii)

0.5
(iii)

8.5
(iv)

2.5
(v)

7.5

Question 20

20.

A die is thrown 100 times. Prime numbers appeared on the upper face 60 times. If a die is thrown at random, what is the probability of getting a prime number?

(i)

3
5
(ii)

2
3
(iii)

2
5
(iv)

4
5

Question 21

21.

A die is thrown 560 times. The number 3 appears on the upper face 86 times. Now the die is thrown at random. What is the probability of getting a 3 ?

(i)

44
281
(ii)

237
280
(iii)

11
70
(iv)

3
20
(v)

43
280

Question 22

22.

A die is thrown 375 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

35

45

50

75

65

105

If the die is thrown again randomly, find the probability of getting 3 as outcome.

(i)

1
15
(ii)

2
15
(iii)

13
15
(iv)

3
16
(v)

1
5

Question 23

23.

On a particular day, at a crossing in a city, the various types of 135 vehicles going past during a time-interval were observed as under:

Type of Vehicle

Two-wheeler

Four-wheeler

Three-wheeler

Frequency

30

45

60

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

(i)

2
9
(ii)

7
9
(iii)

1
9
(iv)

3
10
(v)

1
3

Question 24

24.

Which of the following are true?

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

(i)

{b,e}
(ii)

{b,e,c}
(iii)

{d,a,c}
(iv)

{c,e}
(v)

{a,c}

Question 25

25.

In a lottery, there are 18 prizes and 13 blanks. What is the probability of getting a prize?

(i)

13
31
(ii)

19
31
(iii)

17
31
(iv)

19
32
(v)

18
31

Assignment Key