Mathematics for IGCSE & O level - Probability (Section 3)
1
Two events are considered independent if:
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(C)
The outcome of the second event is not affected by the outcome of the first.
2
If the probability of an event is 1, what does this indicate?
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(C)
The event is certain.
3
In a survey of 200 people, 120 preferred coffee, 60 preferred tea, and 20 had no preference. What is the probability that a randomly selected person prefers coffee?
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(B)
3/5
4
In a bag, there are 5 green balls, 3 red balls, and 2 yellow balls. If Jai chooses a ball at random, replaces it, and then chooses again, what is the probability that Jai's choices are red and yellow in any order?
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(B)
3/50
5
If the probability of an event is 0.3, what is the probability of its complement (the event not happening)?
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(C)
0.7
6
The sum of all outcomes from a tree diagram is always what?
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(B)
1
7
A jar has 5 blue marbles and 5 red marbles. What is the probability of drawing a blue marble OR a red marble?
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(C)
1
8
A card is drawn at random from a standard deck of 52 playing cards. What is the probability of drawing a King?
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(A)
1/13
9
A spinner has 4 equal sections: red, blue, green, and yellow. What is the probability the spinner lands on blue?
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(A)
1/4
10
What is the probability of rolling a multiple of 3 when you spin a fair spinner numbered from 1 to 6?
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(B)
1/3
11
A fair coin is tossed twice. Which of the following is(are) correct?
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A
B
D
12
If the probability of an event is 1/3, and it is repeated twice, what is the probability that the event happens exactly once?
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(C)
4/9
13
If the probability of winning a game is 0.6, then the probability of losing is:
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(B)
0.4
14
What is the probability of drawing a king or a queen from a standard deck of 52 cards?
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(C)
4/13
15
Which of the following is correct for the total probability for all the outcomes?
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(C)
1
16
A box contains 5 red, 3 blue, and 2 green marbles. If you pick one marble, replace it, and then pick another, what is the probability of picking a red marble and then a blue marble?
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(A)
3/20
17
In a bag, there are 5 green balls, 3 red balls, and 2 yellow balls. If Jai chooses a ball at random, replaces it, and then chooses again, what is the probability that both of Jai's choices are red?
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(B)
3/25
18
A survey of 50 people showed that 30 preferred vanilla ice cream. What is the relative frequency of preferring vanilla?
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(B)
3/5
19
If the probability of an event happening is 0.2, what is the probability of the event *not* happening?
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(C)
0.8
20
What is the probability of drawing a red ball, not replacing it, and then drawing a red ball again, if there are 7 red balls and 3 yellow balls to begin with?
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(C)
7/30
21
A bag contains 6 red balls and 4 black balls. Gita selects a ball, notes its color and replaces it. What is the probability Gita selects two red balls?
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(A)
0.36
22
What is the probability of getting heads when you flip a fair coin?
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(C)
1/2
23
If event A and event B are independent, which formula correctly calculates the probability of both events happening?
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(C)
P(A and B) = P(A) * P(B)
24
A bag contains 10 balls numbered 1 to 10. What is the probability of drawing an even-numbered ball?
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(A)
1/2
25
A die is rolled. What is the probability of getting a number less than 3?
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(B)
1/3
26
Which of the following is a key point for the probability of an event?
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(B)
number of outcomes that give the event/total number of outcomes
27
A bag contains 3 red marbles and 5 blue marbles. What is the probability of choosing a red marble?
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(A)
3/8
28
What is the probability of getting tails when you flip a fair coin?
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(C)
1/2
29
What is the probability of getting a 5 on a single roll of a standard six-sided die?
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(C)
1/6
30
If two events cannot occur at the same time, they are considered:
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(C)
Mutually exclusive
31
A bag contains 4 blue and 6 green marbles. If a marble is selected at random, what is the probability it is *not* blue?
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(C)
1/10
32
The probability of a certain event occurring is 0.1. What is the probability of the event *not* occurring?
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(B)
0.9
33
A box contains 20 marbles: 8 are red, 7 are blue, and 5 are green. What is the probability of selecting a red marble?
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(B)
7/20
34
In the context of probability, the term 'trials' most closely represents:
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(B)
The total number of times an experiment is performed.
35
A die is rolled twice. What is the probability of rolling a 1 on the first roll and a 6 on the second roll?
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(A)
1/36
36
What is the correct formula for P(A and B) if A and B are independent events?
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(C)
P(A) * P(B)
37
Which statement is true about probability values?
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(B)
Probability values always range from 0 to 1, inclusive.
38
A jar contains 2 red marbles, 3 blue marbles, and 5 green marbles. If you pick one marble, what is the probability it is green?
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(B)
1/2
39
A bag contains 7 white balls, 3 black balls. What's the probability of picking a black ball?
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(A)
3/10
40
If the probability of event A is 0.6, what is the probability of the complement of A (not A)?
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(B)
0.4
41
If the probability of a train arriving on time is 0.7, what is the probability that the train is late on three consecutive days, assuming the events are independent?
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(B)
0.027
42
What is the probability of drawing a face card (Jack, Queen, or King) from a standard deck of 52 cards?
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(C)
12/52
43
Consider a six-sided die. Which of the following events are possible when rolling the die?
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A
B
D
44
The probability of an event is 0.7. What are the odds *against* that event happening?
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(A)
3:7
45
A spinner has 3 equal sections: red, blue, and green. What is the probability of landing on blue?
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(B)
1/3
46
What is the probability of getting a tail when you toss a fair coin?
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(C)
1/2
47
If you flip a fair coin, what is the probability of getting heads?
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(C)
1/2
48
If the probability of rolling a prime number on a six-sided die is 1/2, what is the probability of *not* rolling a prime number?
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(C)
1/2
49
What type of diagram is best used to find the probabilities when dealing with dependent events?
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(C)
Tree Diagram
50
What are the odds against rolling a 6 on a standard six-sided die?
