Mathematics for IGCSE & O level - Probability (Section 1)
1
If two events are independent, how do you calculate the probability of both events occurring?
Răspuns
(C)
Multiply their individual probabilities
2
When is the sum of all the probabilities of the outcomes of an event equal to 1?
Răspuns
(A)
Always
3
What is the relative frequency of an event if it occurs 15 times in 75 trials?
Răspuns
(D)
15/75
4
If a fair die is rolled twice, what is the probability of rolling a 6 on both rolls?
Răspuns
(A)
1/36
5
Which of the following scenarios represents independent events?
Răspuns
B
C
D
6
In a class of 25 students, 10 students are wearing glasses. If a student is selected at random, what is the probability they are *not* wearing glasses?
Răspuns
(B)
3/5
7
A bag contains 8 green balls and 2 white balls. Two balls are selected without replacement. Which is/are the correct approach(es) to find the probability of selecting two balls of different colors?
Răspuns
A
B
C
8
When two events are mutually exclusive, what is the probability of both events occurring?
Răspuns
(A)
0
9
What is the probability of not rolling a 6 on a single roll of a standard six-sided die?
Răspuns
(C)
5/6
10
A jar contains 5 red, 7 green, and 3 blue marbles. What's the probability of choosing a red or green marble?
Răspuns
(D)
4/5
11
If there are 8 green balls and 2 white balls, two balls are selected without replacement. What is the probability of choosing two white balls?
Răspuns
(B)
1/45
12
What are the possible outcomes when tossing a coin?
Răspuns
A
B
13
In a bag with 6 red balls and 4 black balls. What is the probability of selecting 2 black balls, if the ball is not replaced?
Răspuns
(B)
2/15
14
What is the probability of rolling an odd number on a standard six-sided die?
Răspuns
(C)
1/2
15
A spinner is divided into 3 equal sections: red, green, and blue. What is the probability of the spinner landing on green?
Răspuns
(A)
1/3
16
A bag contains 4 red marbles and 6 blue marbles. If you pick one marble at random, what is the probability of picking a blue marble?
Răspuns
(B)
3/5
17
Which of the following pairs of events are mutually exclusive?
Răspuns
A
C
18
A fair six-sided die is rolled. What is the probability of rolling a 2?
Răspuns
(A)
1/6
19
Which events are independent?
Răspuns
A
D
20
If two events are mutually exclusive, which of the following statements is true?
Răspuns
(C)
The events cannot occur at the same time.
21
A spinner has 4 sections: Red, Green, Blue, and Yellow. Which of the following outcomes are possible if the spinner is spun once?
Răspuns
A
C
D
22
A die is rolled twice. What is the probability of getting a 6 on both rolls?
Răspuns
(C)
1/36
23
If the probability of an event is 1, then the event is:
Răspuns
(C)
Certain
24
What are the odds in favor of rolling a 4 on a standard six-sided die?
Răspuns
(A)
1:5
25
If you roll a six-sided die twice, what is the probability of rolling a 3 on the first roll and a 4 on the second roll?
Răspuns
(A)
1/36
26
A box contains 3 red, 5 green, and 2 yellow balls. What is the probability of picking a yellow ball?
Răspuns
(B)
1/5
27
Which of the following is a correct way to represent probability?
Răspuns
A
B
D
28
Which of the following are considered independent events?
Răspuns
A
B
D
29
If events A and B are mutually exclusive, and P(A) = 0.2 and P(B) = 0.3. What is the probability of either A or B?
Răspuns
(B)
0.5
30
What is the probability of *not* getting a tail when flipping a fair coin?
Răspuns
(B)
0.5
31
A spinner is divided into 8 equal sections, numbered 1 through 8. What is the probability of spinning a number greater than 5?
Răspuns
(B)
1/4
32
Which of the following scenarios represent mutually exclusive events?
Răspuns
A
B
D
33
Which events are mutually exclusive when drawing a single card from a standard deck of 52 cards?
Răspuns
B
C
34
In a class, 40% of the students are girls. If a student is selected randomly, what is the probability that the student is a boy?
Răspuns
(C)
0.6
35
What is the probability of flipping a coin and getting tails?
Răspuns
(C)
1/2
36
What is the probability of getting tails when flipping a fair coin?
Răspuns
(C)
1/2
37
A fair coin is flipped twice. What is the probability of getting two heads?
Răspuns
(B)
1/4
38
If two events, A and B, are independent, P(A) = 0.3 and P(B) = 0.6. What is the probability of A or B?
Răspuns
(D)
0.72
39
In a class, 10 students are wearing red shirts, 15 are wearing blue, and 5 are wearing green. What is the probability that a randomly selected student is wearing a blue shirt?
Răspuns
(B)
1/3
40
What is the probability of not getting a tail when you toss a fair coin once?
Răspuns
(C)
1/2
41
If the probability of a train arriving on time is 0.7, and the probability of the train being late is 0.3. What is the probability that the train is late on the first two days, but on time on the third day? (Independent events)
Răspuns
(B)
0.09
42
What is the probability of choosing a yellow ball on the second draw, given that the ball is not replaced?
Răspuns
(A)
Depends on the colour of the first ball chosen
43
What is the definition of relative frequency?
Răspuns
(C)
The ratio of the number of times an event occurs to the total number of trials.
44
What does the term "independent events" signify in probability?
Răspuns
(C)
Events where the occurrence of one does not influence the probability of the other.
45
What is the probability of getting heads when tossing a fair coin?
Răspuns
(C)
1/2
46
A die is rolled. What is the probability of rolling a number greater than 4?
Răspuns
(A)
1/6
47
A box contains 3 red balls, 4 green balls, and 5 blue balls. What is the probability of picking a green or red ball?
Răspuns
(B)
1/2
48
A standard deck of cards contains 52 cards. What is the probability of drawing a card that is a heart?
Răspuns
(C)
1/4
49
If the train is on time for two out of the three days, what is the probability? (Assume the probability of the train being on time is 0.7)
Răspuns
(B)
0.441
50
A card is drawn from a standard deck of 52 cards. What is the probability of drawing a spade?
