Quantitative Aptitude
PROBABILITY MCQs
Probability, Probability I
Total Questions : 775
| Page 7 of 78 pages
Answer: Option D. -> 8
:
D
Given: P(green marble)=23
Since there are 24 marbles, therefore the sample space will be 24 (i.e. the denominator must be 24.)
Let us assume there arexnumberofgreen marbles in the jar.
For an event E, probabilityP(E)=Number of outcomes favorable to ENumber of all possible outcomes of the experiment
⇒P(green marbles)=23=x24
⇒x=16
It implies that there are 16 green marbles in a jar of 24 marbles.
∴Numberofblue marbles=24−16=8.
:
D
Given: P(green marble)=23
Since there are 24 marbles, therefore the sample space will be 24 (i.e. the denominator must be 24.)
Let us assume there arexnumberofgreen marbles in the jar.
For an event E, probabilityP(E)=Number of outcomes favorable to ENumber of all possible outcomes of the experiment
⇒P(green marbles)=23=x24
⇒x=16
It implies that there are 16 green marbles in a jar of 24 marbles.
∴Numberofblue marbles=24−16=8.
Answer: Option D. -> 1
:
D
Total number of trials = 5
Number of trials which resulted in'6' = 5
∴Experimental Probability, P(E)
=Number of trials in which the event happenedTotal number of trials
=55
=1
:
D
Total number of trials = 5
Number of trials which resulted in'6' = 5
∴Experimental Probability, P(E)
=Number of trials in which the event happenedTotal number of trials
=55
=1
Answer: Option A. -> 0
:
A
The highest sum possible when rolling a pair of dice is 12(getting 6 on both dies). So getting a sum of 13 is an impossible event. Hence, the probability is 0.
:
A
The highest sum possible when rolling a pair of dice is 12(getting 6 on both dies). So getting a sum of 13 is an impossible event. Hence, the probability is 0.
Question 64. Indians , Egyptians , Europeans and Australians are residing in a village of area 200 km2. If the area is equally divided between the four countries, what is the probability that a particular person who lands in the village, finds himself in the area occupied by either Indians or Europeans?
Answer: Option D. -> 0.50
:
D
Each countryoccupies an area of 50km2
Probability that the person lands on a land occupied by Indians or Europeans = (50+50)200 = 12 = 0.50
:
D
Each countryoccupies an area of 50km2
Probability that the person lands on a land occupied by Indians or Europeans = (50+50)200 = 12 = 0.50
:
The word TREKKING has 8 characters of which 2 are favourable. Hence, the probability is 28= 14.
Answer: Option B. -> False
:
B
The sum of probabilities of two mutually exclusive events need not be always1.
For example, consider the events “getting a prime number”, and “getting a composite number” for the experiment ofrolling a die. They are mutually exclusive, but the sum of their probabilities is less than 1.
Favorable outcomes for prime no. = 2 , 3, 5
Favorable outcomes for composite no. = 4, 6
P(getting a prime no.) =36=12
P(getting a composite no.) =26=13
12+13≠1. SoThe sum of probabilities of two mutually exclusive events need not be always1.
:
B
The sum of probabilities of two mutually exclusive events need not be always1.
For example, consider the events “getting a prime number”, and “getting a composite number” for the experiment ofrolling a die. They are mutually exclusive, but the sum of their probabilities is less than 1.
Favorable outcomes for prime no. = 2 , 3, 5
Favorable outcomes for composite no. = 4, 6
P(getting a prime no.) =36=12
P(getting a composite no.) =26=13
12+13≠1. SoThe sum of probabilities of two mutually exclusive events need not be always1.
Answer: Option B. -> 45
:
B
Given, total number of glasses =25(20+5)
⇒ Total number of outcomes =25
Let E be the event of getting good glass.
Number ofgood ones =20
⇒ Number of favourable outcomes =20
Probability P(E)=Number of outcomes favourable to ENumber of all possible outcomes of the experiment
=2025=45
∴ The probability of getting a good glass is 45.
:
B
Given, total number of glasses =25(20+5)
⇒ Total number of outcomes =25
Let E be the event of getting good glass.
Number ofgood ones =20
⇒ Number of favourable outcomes =20
Probability P(E)=Number of outcomes favourable to ENumber of all possible outcomes of the experiment
=2025=45
∴ The probability of getting a good glass is 45.
Answer: Option C. -> 16
:
C
The total possible outcomes when a die is rolled twice are:
12345611,11,21,31,41,51,622,12,22,32,42,52,633,13,23,33,43,53,644,14,24,34,44,54,655,15,25,35,45,55,666,16,26,36,46,56,6
Total number of outcomes = 36
Number of ways to get sum as 7= {(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)}
= 6
P(getting sum as 7)=Favourable outcomesTotal possible outcomes
=OutcomehavingsamenumbersTotalOutcomes
=636
=16
:
C
The total possible outcomes when a die is rolled twice are:
12345611,11,21,31,41,51,622,12,22,32,42,52,633,13,23,33,43,53,644,14,24,34,44,54,655,15,25,35,45,55,666,16,26,36,46,56,6
Total number of outcomes = 36
Number of ways to get sum as 7= {(1,6), (2,5), (3,4), (4,3), (5,2), (6,1)}
= 6
P(getting sum as 7)=Favourable outcomesTotal possible outcomes
=OutcomehavingsamenumbersTotalOutcomes
=636
=16
Answer: Option C. -> 14
:
C
Given,
Total number of outcomes = 52
Number of diamonds = 13
Probability of an event, P(E) = =number of favourable outcomestotal number of outcomes
P (getting a card of diamond) = 1352=14
Therefore, probability of getting a card of diamond is 14 .
:
C
Given,
Total number of outcomes = 52
Number of diamonds = 13
Probability of an event, P(E) = =number of favourable outcomestotal number of outcomes
P (getting a card of diamond) = 1352=14
Therefore, probability of getting a card of diamond is 14 .
Answer: Option B. -> sample space
:
B
In probability theory, the sample space of an experiment or random trial is the set of all possible outcomes or results of that experiment.
For example, if we toss a single coin then the chances are that either head willappear or tail will appear,the sample space will be {H}, {T}.
:
B
In probability theory, the sample space of an experiment or random trial is the set of all possible outcomes or results of that experiment.
For example, if we toss a single coin then the chances are that either head willappear or tail will appear,the sample space will be {H}, {T}.