Mathematics for IGCSE & O level - Probability (Section 4)
1
If the probability of an event occurring is 0.25, what is the probability of that event *not* occurring?
Răspuns
(C)
0.75
2
Which of the following are correct when dealing with dependent events?
Răspuns
A
B
D
3
Which statement about probability is true?
Răspuns
(C)
The probability of an event is always a number between 0 and 1, inclusive.
4
Which of the following scenarios represents independent events?
Răspuns
(B)
Flipping a coin and then rolling a die.
5
In a school, 60% of the students are girls and 40% are boys. What is the probability of randomly selecting a boy?
Răspuns
(A)
0.4
6
A box contains 3 red, 4 blue and 2 green balls. What is the probability of choosing a blue ball?
Răspuns
(B)
4/9
7
A jar contains 4 red, 5 blue and 3 green marbles. What is the probability of drawing a marble that is not red?
Răspuns
(D)
7/12
8
What is the expected frequency?
Răspuns
(C)
Number of trials multiplied by the probability of the event occurring
9
In a standard deck of cards, are the events of drawing a King and drawing a Spade mutually exclusive?
Răspuns
(B)
No, because the King of Spades is a possible outcome.
10
If the probability of winning the first hockey match is 0.6, and if they win the first match, the probability of winning the second is 0.7, otherwise 0.4. What is the probability they win one of the first two matches?
Răspuns
(A)
0.66
11
In a bag with 6 red balls and 4 black balls. What is the probability of selecting one of each color, if the ball is not replaced?
Răspuns
(C)
12/20
12
What are the odds in favor of rolling an even number on a standard six-sided die?
Răspuns
(C)
1:1
13
If the probability of an event is 0.75, what is the probability that the event will *not* occur?
Răspuns
(A)
0.25
14
A basket contains 7 apples and 3 oranges. If a piece of fruit is selected at random, what is the probability it is an apple?
Răspuns
(B)
7/10
15
In a school, 70% of the students are female. If a student is chosen at random, what's the probability the student is male?
Răspuns
(A)
0.3
16
What is the relative frequency of an event?
Răspuns
(A)
number of times an outcome occurs / total number of trials
17
If the first ball chosen from a bag is not replaced, the second draw is an example of what?
Răspuns
(B)
Dependent events
18
If a fair six-sided die is rolled, what is the probability of rolling a number greater than 4?
Răspuns
(A)
1/6
19
A bag contains 4 red and 6 white marbles. If a marble is selected randomly, what is the probability that it is white?
Răspuns
(B)
3/5
20
What is the probability of drawing a black card (club or spade) from a standard deck of 52 playing cards?
Răspuns
(A)
1/2
21
What are the values that probability can have?
Răspuns
(D)
both b and c
22
If the probability of an event occurring is 0.8, what are the odds against that event happening?
Răspuns
(B)
4:1
23
A spinner has 5 equal sections: red, blue, green, yellow, and purple. What is the probability of spinning either red or blue?
Răspuns
(B)
2/5
24
What is relative frequency an estimate of?
Răspuns
(A)
probability
25
which method is useful for solving problems with dependent events?
Răspuns
(C)
Tree diagrams
26
If the probability of an event is 0, what does that mean?
Răspuns
(C)
The event is impossible.
27
Given that the probability of Sarah's bus being late on any day is 0.2. What is the probability that Sarah's bus is late on both of two days?
Răspuns
(B)
0.04
28
What is the result of the calculation: 1 - P(event occurring)?
Răspuns
(C)
Probability of event not occurring.
29
Which events are mutually exclusive when rolling a die and flipping a coin?
Răspuns
B
C
30
A bag contains 6 blue balls and 4 red balls. If a ball is chosen at random, what is the probability of selecting a red ball?
Răspuns
(B)
2/5
31
For independent events A and B, the probability of both A and B occurring is calculated by:
Răspuns
(C)
P(A) x P(B)
32
What is the complement of the event "rolling an even number" on a die?
Răspuns
(A)
Rolling an odd number
33
If two events are independent, how do you calculate the probability of both events occurring?
Răspuns
(B)
Multiply the probabilities of each event.
34
Which of the following statement(s) is/are correct regarding a probability tree diagram?
Răspuns
A
C
35
What is the probability of drawing a red ball on the first draw, not replacing it, and drawing a yellow ball on the second draw if there are 7 red balls and 3 yellow balls?
Răspuns
(B)
3/10
36
A bag contains 4 red marbles and 6 blue marbles. Which events are *independent* if you draw two marbles with replacement?
Răspuns
A
B
C
37
What type of diagram can illustrate the outcomes and probabilities of two or more events?
Răspuns
(C)
Probability Tree Diagram
38
If two events, A and B, are mutually exclusive and P(A) = 0.3 and P(B) = 0.4, what is P(A or B)?
Răspuns
(B)
0.7
39
A standard deck of cards is shuffled. What is the probability of drawing a card that is a Queen?
Răspuns
(B)
1/13
40
A die is rolled. What is the probability of rolling a number less than 5?
Răspuns
(C)
2/3
41
If the probability of an event occurring is 0.3 and the probability of a second independent event occurring is 0.4, what is the probability of both events occurring?
Răspuns
(B)
0.12
42
In a bag, there are 5 red marbles, 3 blue marbles, and 2 green marbles. What is the probability of randomly selecting a marble that is either red or blue?
Răspuns
(D)
8/10
43
The probability of a certain event occurring is 0.6. What is the probability of this event *not* occurring?
Răspuns
(B)
0.4
44
In the context of probability, what does 'mutually exclusive' mean?
Răspuns
(B)
The events cannot occur at the same time.
45
What is the complement of the event 'rolling an even number' on a six-sided die?
Răspuns
(B)
Rolling an odd number
46
What is the probability of drawing a face card (Jack, Queen, or King) from a standard deck of 52 playing cards?
Răspuns
(C)
3/13
47
What is the probability of rolling a 7 with two standard six-sided dice?
Răspuns
(A)
1/6
48
Consider a survey about favorite ice cream flavors. 30 people chose chocolate, 20 chose vanilla, and 10 chose strawberry. If a person is randomly selected, what is the probability that the person chose chocolate?
Răspuns
(C)
1/2
49
A spinner has 4 equal sections colored red, blue, green, and yellow. What is the probability that the spinner lands on a color that is not red?
Răspuns
(C)
3/4
50
A sample space diagram is a two-way table listing all possible outcomes of what?
