EduSahara™ Worksheet

Question 1

1.

Which of the following are true?

a)

P(E) = 1 - P(
E
)

b)

P(E) + P(
E
) = 0

c)

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

d)

P(E) - P(
E
) = 0

e)

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

(i)

{b,a}
(ii)

{d,c,a}
(iii)

{a,c}
(iv)

{d,c}
(v)

{e,b,a}

Question 2

2.

Two unbiased coins are tossed simultaneously. Find the probability of getting at most one head.

(i)

1
4
(ii)

3
4
(iii)

4
5
(iv)

1
(v)

1
2

Question 3

3.

There are 68 students in a class room of whom 32 are boys and 36 are girls. From these students, one is choosen at random. What is the probability that the choosen student is a boy ?

(i)

9
17
(ii)

1
2
(iii)

8
17
(iv)

7
17

Question 4

4.

Three unbiased coins are tossed simultaneously. Find the probability of getting at least two heads.

(i)

3
4
(ii)

1
2
(iii)

5
6
(iv)

2
3
(v)

4
5

Question 5

5.

Two coins are tossed simultaneously 80 times and it was observed that both tails appeared 25 times. If two coins are tossed simultaneously at random, what is the probability of getting both tails?

(i)

6
17
(ii)

1
4
(iii)

3
8
(iv)

11
16
(v)

5
16

Question 6

6.

Which of the following are true?

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

(i)

{c,a,d}
(ii)

{b,e,d}
(iii)

{a,d}
(iv)

{b,e}
(v)

{d,e}

Question 7

7.

75 cards are numbered 1,2,3,....75 and put in a box and mixed thoroughly. A card is drawn at random. What is the probability that the number on the drawn card is divisible by 5?

(i)

2
5
(ii)

0
(iii)

4
5
(iv)

1
5
(v)

1
3

Question 8

8.

On a particular day, at a crossing in a city, the various types of 130 vehicles going past during a time-interval were observed as under:

Type of Vehicle

Two-wheeler

Four-wheeler

Three-wheeler

Frequency

30

40

60

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

(i)

4
13
(ii)

5
14
(iii)

9
13
(iv)

3
13
(v)

5
13

Question 9

9.

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

16

3

15

18

29

2

16

2

What is the empirical probability that an engineer lives greater than 3 km from her place of work?

(i)

5
8
(ii)

1
2
(iii)

2
3
(iv)

3
4
(v)

3
8

Question 10

10.

A lot of 26 bulbs contain 15 defective ones. One bulb is drawn at random from the lot. What is the probability that this bulb is defective ?

(i)

7
13
(ii)

8
13
(iii)

15
26
(iv)

11
26
(v)

16
27

Question 11

11.

One card is drawn at random from a well shuffled deck of 52 cards. What is the probability that the card drawn is either a red card or a queen?

(i)

1
13
(ii)

7
13
(iii)

1
52
(iv)

3
13
(v)

1
26

Question 12

12.

When two dice are thrown simultaneously, how many elementary events are possible?

(i)

38
(ii)

36
(iii)

33
(iv)

35
(v)

37

Question 13

13.

A die is thrown twice. What is the probability that 1 will come atleast once?

(i)

25
36
(ii)

5
18
(iii)

12
37
(iv)

1
3
(v)

11
36

Question 14

14.

In a musical chair game, the person playing the music has been advised to stop playing the music at any time with in 2 minutes after she starts playing. What is the probabilty that the music will stop within the first half-minute after starting?

(i)

2
5
(ii)

3
4
(iii)

1
4
(iv)

0
(v)

1
2

Question 15

15.

An unbiased die is thrown once. Find the probability of getting a 4?

(i)

2
7
(ii)

5
6
(iii)

1
6
(iv)

0
(v)

1
3

Question 16

16.

A bag contains 25 gray marbles, 60 orange marbles, 50 white marbles and 15 blue marbles. One marble is drawn at random from the bag. Find the probability that the marble drawn is neither white nor orange.

(i)

1
5
(ii)

5
16
(iii)

1
3
(iv)

11
15
(v)

4
15

Question 17

17.

In a lottery, there are 24 prizes and 19 blanks. What is the probability of getting a prize?

(i)

25
44
(ii)

24
43
(iii)

25
43
(iv)

19
43
(v)

23
43

Question 18

18.

Geetha and Keerthi are friends. What is the probability that both will have same birthdays? (ignoring a leap year).

(i)

1
183
(ii)

2
365
(iii)

0
(iv)

1
365
(v)

364
365

Question 19

19.

A bag contains 20 white marbles, 28 pink marbles, 14 orange marbles and 8 blue marbles. One marble is drawn at random from the bag. Find the probability that the marble drawn is blue or white.

(i)

1
5
(ii)

3
5
(iii)

1
2
(iv)

2
5

Question 20

20.

Three coins are tossed simultaneously 245 times with the following frequencies of different outcomes :

Outcome

3 heads

2 heads

1 heads

No heads

Frequency

30

50

80

85

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

(i)

17
49
(ii)

16
49
(iii)

17
50
(iv)

33
49
(v)

15
49

Question 21

21.

A lot of 39 bulbs contain 14 defective ones. One bulb is drawn at random from the lot. Suppose the bulb drawn is not defective and is not replaced. Now one bulb is drawn at random from the rest. What is the probability that this bulb is not defective ?

(i)

7
19
(ii)

11
19
(iii)

13
19
(iv)

12
19
(v)

13
20

Question 22

22.

What is the probability of a sure event?

(i)

1
2
(ii)

3
4
(iii)

0
(iv)

1
4
(v)

1

Question 23

23.

Suppose a die is thrown on a rectangular region as shown below. What is the probability that it will land inside the circle of diameter 16.00 cm?

(i)

47
147
(ii)

1501
2205
(iii)

703
2205
(iv)

705
2206
(v)

704
2205

Question 24

24.

An unbiased die is thrown once. Find the probability of getting a number between 2 and 4?

(i)

5
6
(ii)

1
6
(iii)

2
7
(iv)

0
(v)

1
3

Question 25

25.

A die is thrown 335 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

30

35

50

60

75

85

If the die is thrown again randomly, find the probability of getting 1 as outcome.

(i)

7
67
(ii)

61
67
(iii)

7
68
(iv)

6
67
(v)

5
67

Assignment Key