Mathematics for IGCSE & O level - Probability (Section 6)
1
There are 6 red balls and 4 blue balls. What is the probability of selecting two red balls without replacement?
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(A)
9/25
2
A committee of 3 people is to be selected from a group of 5 men and 7 women. If the selection is random, and the events of selecting each person are considered independent, what is the probability of selecting 3 women?
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(A)
(7/12) * (6/11) * (5/10)
3
A weather forecast states a 20% chance of rain. What are the odds against rain (in fractional form)?
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(D)
4/1
4
A weather forecast predicts a 40% chance of rain. What is the probability that it will *not* rain?
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(C)
60%
5
Which of the following events are mutually exclusive?
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A
B
D
6
If the odds of a team winning a game are 2:5, what is the probability that the team *loses* the game?
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(B)
5/7
7
If the probability of an event occurring is 0.4, what is the probability of the event not occurring?
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(C)
0.6
8
Which of the following best defines a sample space?
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(C)
The set of all possible outcomes of an experiment.
9
A bag contains 5 red marbles and 7 blue marbles. What is the probability of selecting a red marble?
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(C)
5/12
10
What is the probability of rolling an even number on a standard six-sided die?
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(C)
1/2
11
A bag contains 5 red and 5 blue marbles. What is the probability of selecting a red marble *or* a blue marble?
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(D)
1
12
Which of the following scenarios describes independent events?
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(B)
Flipping a coin and rolling a six-sided die.
13
Which of the following events are mutually exclusive?
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A
D
14
In probability, what does the term 'event' refer to?
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(A)
A set of one or more outcomes.
15
Two dice are rolled. What is the probability that the sum of the numbers is 10?
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(B)
1/12
16
What are the main characteristics of independent events?
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(B)
The outcome of one event does not affect the outcome of the other.
17
If the probability of an event occurring is 2/3, what is the probability of that event *not* occurring?
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(A)
1/3
18
What is a key difference in a tree diagram between independent and dependent events?
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(B)
The probabilities on the second set of branches are different.
19
When are two events considered mutually exclusive?
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(B)
When they cannot both occur at the same time.
20
What is the probability of drawing an ace from a standard deck of 52 playing cards?
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(B)
4/52
21
Two six-sided dice are rolled. What is the probability the sum of the two dice is 1?
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(A)
0
22
What is the relationship between probability and relative frequency?
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(B)
Relative frequency is an estimate of probability.
23
A fair coin is flipped once. What is the probability of getting heads?
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(C)
1/2
24
A bag contains 5 red marbles and 3 blue marbles. What is the probability of selecting a red marble, replacing it, and then selecting a blue marble?
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(A)
15/64
25
If the probability of it raining is 0.3, what is the probability that it does not rain?
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(B)
0.7
26
If the probability of an event is 0.7, what are the odds *against* that event happening?
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(B)
3:7
27
What is the probability of getting tails when you flip a fair coin?
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(C)
1/2
28
A fair six-sided die is rolled. What is the probability of rolling a number less than 3?
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(B)
2/6
29
If a train arrives on time with a probability of 0.7, what's the probability the train will be late on three consecutive days?
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(C)
0.027
30
A spinner has 4 equal sections: red, blue, green, and yellow. What is the probability the spinner lands on red or yellow?
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(B)
1/2
31
What is the fundamental principle behind calculating the probability of independent events?
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(C)
Multiplying the individual probabilities.
32
If the probability that Gary and Rashna were both born on a Monday is equal likelihood. What is the probability?
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(B)
1/49
33
What is a characteristic of independent events?
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(B)
The outcome of one has no impact on the probability of the other.
34
Which of the following statements about probabilities are true?
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B
C
D
35
Two dice are rolled. What is the probability the sum of the numbers is an even number?
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(B)
1/2
36
A bag contains 3 red marbles, 4 blue marbles, and 2 green marbles. What is the probability of randomly selecting a blue marble?
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(B)
4/9
37
If the probability of an event happening is 0.2, what is the probability of that event *not* happening?
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(C)
0.8
38
In a survey of 100 people, 60 like cats and 30 like dogs. If liking cats and dogs is independent, what is the probability a person likes both cats and dogs?
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(B)
0.18
39
A die is rolled. What is the probability of rolling a number greater than 2?
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(D)
2/3
40
If the probability of winning a lottery is 1/1,000,000, what does this mean?
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(C)
You have a very small chance of winning.
41
What is the key difference between independent and dependent events in terms of calculating probabilities?
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(D)
The probabilities on the second set of branches in a tree diagram are the same for independent events and different for dependent events.
42
What are the different ways to express the probability of an event?
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A
B
D
43
Which of the following statements are true regarding probabilities?
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A
B
C
44
What is the range of possible values for any probability?
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B
C
45
If the probability of Event A is 0.6 and the probability of Event B is 0.4, and the events are independent, what is the probability of A happening and B not happening?
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(B)
0.36
46
If the probability of an event occurring is 3/5, what is the probability that the event will *not* occur?
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(A)
2/5
47
A spinner has 8 equal sections numbered 1 through 8. What is the probability of spinning an odd number?
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(B)
1/2
48
A die is rolled. What is the probability of getting a number less than or equal to 2?
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(B)
2/6
49
Which of the following events are *dependent*?
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A
C
50
Two dice are rolled. What is the probability of rolling a double (both dice show the same number)?
