Probability · Mathematics · NDA

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MCQ (Single Correct Answer)

1

A bag contains 5 black and 4 white balls. A man selects two balls at random. What is the probability that both of these are of the same colour?

NDA Mathematics 21 April 2024
2
If a random variable $(x)$ follows binomial distribution with mean 5 and variance 4 , and $5^{23} P(X=3)=\lambda 4^\lambda$, then what is the value of $\lambda$ ?
NDA Mathematics 21 April 2024
3

If the letters of the word 'TIRUPATI' are written down at random, then what is the probability that both Ts are always consecutive?

NDA Mathematics 21 April 2024
4

Let $m = 77^n$. The index $n$ is given a positive integral value at random. What is the probability that the value of $m$ will have $1$ in the units place?

NDA Mathematics 21 April 2024
5

Three different numbers are selected at random from the first 15 natural numbers. What is the probability that the product of two of the numbers is equal to third number?

NDA Mathematics 21 April 2024
6

What is the minimum value of $P(A) + P(B)$?

NDA Mathematics 21 April 2024
7

What is the maximum value of $P(A) + P(B)$?

NDA Mathematics 21 April 2024
8

What is the minimum value of $P(B \cap C)$?

NDA Mathematics 21 April 2024
9

What is the maximum value of $P(B \cap C)$?

NDA Mathematics 21 April 2024
10

What is the value of $n$?

NDA Mathematics 21 April 2024
11

What is the value of $p + q$?

NDA Mathematics 21 April 2024
12
Three dice are thrown. What is the probability of getting a sum which is a perfect square?
NDA Mathematics 3 September 2023
13

A, B, C and D are mutually exclusive and exhaustive events.

If 2P(A) = 3P(B) = 4P(C) = 5P(D), then what is 77P(A) equal to ?

NDA Mathematics 3 September 2023
14
Two distinct natural numbers from 1 to 9 are picked at random. What is the probability that their product has 1 in its unit place?
NDA Mathematics 3 September 2023
15
Two dice are thrown. What is the probability that difference of numbers on them is 2 or 3 ?
NDA Mathematics 3 September 2023
16
The probability that a person recovers from a disease is 0.8. What is the probability that exactly 2 persons out of 5 will recover from the disease?
NDA Mathematics 3 September 2023
17
Suppose that there is a chance for a newly constructed building to collapse, whether the design is faulty or not. The chance that the design is faulty is 10%. The chance that the building collapses is 95% if the design is faulty, otherwise it is 45%. If it is seen that the building has collapsed, then what is the probability that it is due to faulty design?
NDA Mathematics 3 September 2023
18
A fair coin is tossed 6 times. What is the probability of getting a result in the 6th toss which is different from those obtained in the first five tosses ?
NDA Mathematics 3 September 2023
19
In a class, there are n students including the students P and Q. What is the probability that P and Q sit together if seats are assigned randomly?
NDA Mathematics 3 September 2023
20
What is the probability that all three boys sit together?
NDA Mathematics 3 September 2023
21
What is the probability that boys and girls sit alternatively?
NDA Mathematics 3 September 2023
22
What is the probability that no two girls sit together?
NDA Mathematics 3 September 2023
23
What is the probability that P and Q take the two end positions?
NDA Mathematics 3 September 2023
24
What is the probability that Q and U sit together?
NDA Mathematics 3 September 2023
25

Let A and B be two independent events such that

P(A̅) = 0.7, P(B̅) = k, P(A ∪ B) = 0.8, what is the value of k ?

NDA Mathematics 16 April 2023
26
A biased coin with the probability of getting head equal to $\frac{1}{4}$ is tossed five times. What is the probability of getting tail in all the first four tosses followed by head ? 
NDA Mathematics 16 April 2023
27
A coin is biased so that heads comes up thrice as likely as tails. In four independent tosses of the coin, what is probability of getting exactly three heads ?
NDA Mathematics 16 April 2023
28
Let X and Y be two random variables such that X + Y = 100. If X follows Binomial distribution with parameters n = 100 and p = $\frac{4}{5}$, what is the variance of Y?  
NDA Mathematics 16 April 2023
29
One bag contains 3 white and 2 black balls, another bag contains 2 white and 3 black balls. Two balls are drawn from the first bag and put it into the second bag and then a ball is drawn from the second bag. What is the probability that it is white ? 
NDA Mathematics 16 April 2023
30
Three dice are thrown. What is the probability that each face shows only multiples of 3 ? 
NDA Mathematics 16 April 2023
31
What is the probability that the month of December has 5 Sundays ?
NDA Mathematics 16 April 2023
32
A natural number n is chosen from the first 50 natural numbers. What is the probability that $n+\frac{50}{n}<50 $ ?
NDA Mathematics 16 April 2023
33
What is the probability of getting a composite number in the list of natural numbers from 1 to 50?
NDA Mathematics 4 September 2022
34
If n > 7, then what is the probability that C(n, 7) is a multiple of 7?
NDA Mathematics 4 September 2022
35
Two numbers x and y are chosen at random from a set of the first 10 natural numbers. What is the probability that (x + y) is divisible by 4 ?
NDA Mathematics 4 September 2022
36
A number x is chosen at random from first n natural numbers. What is the probability that the number chosen satisfies x + $\frac{1}{\text{x}}$ > 2 ?
NDA Mathematics 4 September 2022
37
Three fair dice are tossed once. What is the probability that they show different numbers that are in AP?
NDA Mathematics 4 September 2022
38
If P(A) = 0.5, P(B) = 0.7 and P(A ∩ B) = 0.3, then what is the value of P(A' ∩ B') + P(A' ∩ B) + P(A ∩ B') ?
NDA Mathematics 4 September 2022
39
Five coins are tossed once. What is the probability of getting at most four tails ?
NDA Mathematics 4 September 2022
40
Three fair dice are thrown. What is the probability of getting a total greater than or equal to 15 ?
NDA Mathematics 4 September 2022
41
The probability that a person hits a target is 0.5. What is the probability of at least one hit in 4 shots ?
NDA Mathematics 4 September 2022
42
During war, one ship out of 5 was sunk on an average in making a certain voyage. What is the probability that exactly 3 out of 5 ships would arrive safely?
NDA Mathematics 4 September 2022
43
A card is drawn from a pack of 52 cards. A gambler bets that it is either a spade or an ace. The odds against his winning are
NDA Mathematics 4 September 2022
44
The completion of a construction job may be delayed due to strike. The probability of strike is 0.6. The probability that the construction job gets completed on time if there is no strike is 0.85 and the probability that the construction job gets completed on time if there is a strike is 0.35. What is the probability that the construction job will not be completed on time ?
NDA Mathematics 4 September 2022
45
Two digits out of 1, 2, 3, 4, 5 are chosen at random and multiplied together. What is the probability that the last digit in the product appears as 0?
NDA Mathematics 10 April 2022
46
What is $P (G \cap \overline T)$ equal to?
NDA Mathematics 10 April 2022
47
What is $P(G | \overline T) $ equal to?
NDA Mathematics 10 April 2022
48
What is $P(\overline T | \overline G)$ equal to?
NDA Mathematics 10 April 2022
49
What is the probability that exactly 3 out of 6 workers suffer from a disease?
NDA Mathematics 10 April 2022
50
What is the probability that no one out of 6 workers suffers from a disease?
NDA Mathematics 10 April 2022
51
What is the probability that at least one out of 6 workers suffer from a disease ?
NDA Mathematics 10 April 2022
52
Let two events A and B be such that P(A) = L and P(B) = M. Which one of the following is correct?
NDA Mathematics 18 April 2021
53

If $\rm P(A\cup B)=\dfrac{5}{6}, P(A\cap B)=\dfrac{1}{3}\:and\:P(\bar A)=\dfrac{1}{2}$, then which of the following is/are correct?

1. A and B are independent events.

2. A and B are mutually exclusive events.

Select the correct answer using the code given below.

NDA Mathematics 18 April 2021
54
A coin is tossed twice. If E and F denote occurrence of head on first toss and second toss respectively, then what is P(E ∪ F) equal to?
NDA Mathematics 18 April 2021
55
In a binomial distribution, the mean is $\dfrac{2}{3}$ and variance is $\dfrac{5}{9}$. What is the probability that random variable D = 2?
NDA Mathematics 18 April 2021
56

If A and B are two events such that $\rm P(A)=\dfrac{3}{4} \:and\: P(B)=\dfrac{5}{8}$, then consider the following statements:

1. The minimum value of P(A ∪ B) is $\dfrac{3}{4}.$

2. The maximum value of P(A ∩ B) is $\dfrac{5}{8}.$

Which of the above statements is/are correct?

NDA Mathematics 18 April 2021
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