Download mathematics worksheet-ix probability

MATHEMATICS WORKSHEET-IX
PROBABILITY
LEVEL 1
1. Probability of a sure event is __________________.
2. Probability of an impossible event is ___________.
3. Probability of an event of a trial is always between ______ and _______.
4. Which of the following cannot be the empirical probability?
i) 0.5
ii) 25%
𝟏
𝟕
iii) 1𝟐iv) 𝟗
5. Two coins are tossed simultaneously and we get:
i) 2 heads: 105 times
ii) One head: 275 times
iii) No head: 120 times
Find the probability of getting
i) 2 heads
ii) one head iii) no head
6. Sum of the probability of all events of a trial is ___________.
LEVEL 2
7. Two dice are thrown 400 times. Each time sum of two numbers appearing on their tops is
noted as given in the following table.
sum
2
3
4
5
6
7
8
9
10
11
12
frequency 14
20
32
45
62
65
60
43
36
18
5
What is the probability of getting sum i) 5 ii) more than 10 iii) between 5 and 10
8. Probability of getting an event is 0.25. Find the probability of not getting that event.
9. A bag contains 5 red balls and 7 blue balls. Find the probability of getting:
i) A blue ball
ii) A blue ball
10. A coin is tossed once. What is the probability of getting: i) a tail
11. A dice is thrown once. Find the probability of getting:
ii) a head
i) A prime number
iv) An odd number
ii) A perfect square
iii) A number less than 3
v) A number less than or equal to 5
12. A blood donation camp was organized in a colony. Thirty people donated their blood. The
blood groups of these 30 people were recorded as follows:
A, B, O, O , AB , O , A , O ,B , A , O, B, O ,O, A , AB , O, A , A , O , O , AB , A , B , A , O , B ,
A , B, O
Answer the following:
If one person from this group is selected, what is the probability that his blood group is:
i) AB
ii) O
13. A survey found that the ages of the workers in a factory is distributed as given below:
Age
20-29 30-39 40-49 50-59
60 or above
No: of
38
27
86
46
3
workers
If a person is selected at random, find the probability that the person is:
i) 40 years or more ii) having age from 30 to 39 years iii) under 60 but over 39 years
14. A die is thrown 1000 times with the frequencies for the outcomes 1, 2 , 3, 4 , 5 and 6 as
given in the following table:
Outcomes
1
2
3
4
5
6
Frequencies
179
150
157
149
175
190
Find the probability of getting:
i) A prime number as outcome
ii) number greater than 5 as outcome.
LEVEL 3
15. 3 coins are tossed simultaneously 150 times with the following frequency
outcomes
frequency
3 heads 2 heads 1 head No head
20
80
30
20
Compute the probability of getting: i) two heads ii) at least two heads
16. In a One Day International, a batsman played 40 balls. The runs scored are as follows
Runs scored
No: of balls
0
13
1
15
2
5
3
1
Find the probability that the batsman will score:
4
4
6
2
i) 6 runs ii) 4 or 6 runs iii) 0 or 4 or 6 runs
17. Cards with numbers 1, 2, 3………….100 are placed in a box and mixed thoroughly. One card
is drawn. What is the probability that the card drawn is:
i) A prime number less than 30
ii) A multiple of 5 and 7
iii) A multiple of 5 or 7
18. In n trials of a random experiment, if an event E happens m times, find P(E).
19. A bag contains 5 red balls and some blue balls. If the probability of drawing a blue ball is
double that of a red ball, find the number of blue balls in the bag.
20. A jar contains 24 marbles. Among them some are green and some are blue. If a marble is
𝟐
drawn at random from the jar, the probability that it is green is 𝟓 . Find the number of blue
balls in the jar.
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%