Mathematics for IGCSE & O level - Probability (Section 8)
1
What is the probability of rolling an odd number on a standard six-sided die?
Answer
(C)
1/2
2
If the chance of rain is 40%, and the chance of wind is 20%, what is the chance of both events happening, assuming they're independent?
Answer
(B)
8%
3
A pin falls 300 times. The probability of the pin landing point up is 0.3. How many times is the pin expected to land point up?
Answer
(B)
90
4
A study found that 20% of a population has a certain disease. What is the probability that a randomly selected person *does not* have the disease?
Answer
(B)
80%
5
Anna selects a ball from a bag, notes its color, replaces it, and selects another. There are 4 green and 1 blue ball. What is the probability that the first ball is green and the second is blue?
Answer
(A)
4/25
6
A fair coin is flipped. What is the probability of getting heads?
Answer
(C)
0.5
7
If the probability that Sarah's bus is late on any given day is 0.2, what is the probability that her bus is late on just one of the two days?
Answer
(A)
0.04
8
When is the multiplication rule applicable to probability calculations?
Answer
(C)
For independent events.
9
In the case of drawing a ball from a bag without replacement. If there are seven blue and three red balls and you pick two balls. What is the probability of picking two blue balls?
Answer
(B)
42/90
10
A bag contains 7 red and 3 white marbles. What is the probability of selecting a white marble?
Answer
(C)
3/10
11
What is the definition of probability
Answer
(C)
The likelihood of an event occurring.
12
A basketball player makes 70% of their free throws. What is the probability they *miss* a free throw?
Answer
(A)
30%
13
What is the formula for calculating the probability of two independent events, A and B, both occurring?
Answer
(C)
P(A and B) = P(A) * P(B)
14
Which of the following are true regarding dependent events?
Answer
A
B
15
A spinner has four equal sections colored red, blue, green, and yellow. What is the probability of the spinner landing on red or blue?
Answer
(B)
1/2
16
What is the probability of rolling a number less than 5 on a six-sided die?
Answer
(D)
4/6
17
In the context of independent events, what is the most important aspect of the outcome of the events?
Answer
(B)
The events are not related
18
What are the two possible outcomes when flipping a coin?
Answer
A
B
19
A company surveyed 100 customers about their favorite ice cream flavors. 50 chose vanilla, 30 chose chocolate, and 20 chose strawberry. What is the probability that a randomly selected customer prefers chocolate?
Answer
(B)
3/10
20
A spinner has 4 equal sections: red, green, blue, and yellow. What is the probability it lands on blue?
Answer
(A)
1/4
21
If two events, A and B, are mutually exclusive, what can we say about the probability of both happening at the same time?
Answer
(B)
P(A and B) = 0
22
What does 'mutually exclusive' mean in the context of probability?
Answer
(B)
The events cannot occur at the same time.
23
A bag contains only red and white marbles. If the probability of drawing a red marble is 0.4, what is the probability of drawing a white marble?
Answer
(C)
0.6
24
What is the probability of rolling a 7 on a standard six-sided die?
Answer
(A)
0
25
Which of the following are examples of mutually exclusive events?
Answer
A
B
26
A jar contains 5 green and 7 yellow marbles. What is the probability that a randomly selected marble is yellow?
Answer
(B)
7/12
27
If the probability of an event occurring is 0.6, what is the probability of the event *not* occurring?
Answer
(A)
0.4
28
If the probability that Salima walks to school is 0.5, cycles is 0.2, and she goes by bus is 0.3. If she walks, the probability she's on time is 0.2. If she cycles, it's 0.1. If she goes by bus, it is 0.4. What is the probability that, on any given day, she is on time for school?
Answer
(B)
0.27
29
What does the probability of an event represent?
Answer
(C)
The likelihood of the event occurring.
30
What is the main characteristic of a dependent event?
Answer
(A)
The event influences the result of the other
31
How do you calculate the expected frequency of an event?
Answer
(D)
Probability of the event occurring * total number of observations of the event.
32
A card is drawn randomly from a standard deck. What is the probability of drawing a spade?
Answer
(B)
1/13
33
A fair coin is tossed. What is the probability of getting tails?
Answer
(C)
0.5
34
Which of the following methods can be used to find the probability?
Answer
A
B
D
35
When are two events considered independent?
Answer
(B)
When the outcome of the second event is not affected by the outcome of the first event.
36
Consider the statement: "The probability of an event happening is 0.8." What does this tell you?
Answer
B
C
37
If the probability of an event occurring is 1, what does this mean?
Answer
(C)
The event is certain to occur.
38
What is the probability of rolling an odd number on a standard six-sided die?
Answer
(C)
1/2
39
If the probability of Imran's bus being late is 0.2, what is the probability of his bus being late for three consecutive mornings (assuming independence)?
Answer
(A)
0.008
40
A bag contains 4 green balls and 1 blue ball. What is the probability of picking two green balls if the first ball is replaced?
Answer
(A)
16/25
41
A die is rolled. What is the probability of getting a number greater than 4?
Answer
(A)
1/6
42
What is the probability of the event not occurring, given the probability is 0.7?
Answer
(A)
0.3
43
What is the probability of drawing a black jack from a standard deck of 52 cards?
Answer
(B)
2/52
44
What is the key characteristic of mutually exclusive events?
Answer
(C)
They cannot occur at the same time.
45
Which of the following situations demonstrate independent events?
Answer
B
D
46
A company surveyed its employees about their favorite ice cream flavors. 30% chose vanilla, 40% chose chocolate, and 30% chose strawberry. What is the probability that an employee chosen at random *doesn't* choose vanilla?
Answer
(D)
70%
47
If the probability of event A is 0.3 and the probability of event B is 0.4, what is the probability of both events happening if the events are independent?
Answer
(A)
0.12
48
What is the probability of picking a black card from a standard deck of 52 playing cards?
Answer
(B)
1/2
49
A standard deck of cards is shuffled and a card is drawn. What is the probability the card is a heart?
Answer
(C)
1/4
50
In a set of data, if an event has a relative frequency of 0.25, what does this mean?
