(Mathematics) NDA/NA SOLVED PAPER 2024 – I (101 to 120)

Total Questions: 20

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?

Correct Answer: (c) 4/9
Solution:

2. If a random variable (x) follows binomial distribution with mean 5 and variance 4, 5²³ P(X = 3) = λ 4 λ , then what is the value of ?

Correct Answer: (c) 23
Solution:

3. From data (-4, 1), (-1, 2), (2, 7) and (3, 1), the regression line of y on x is obtained as y = a + bx then what is the value of 2a + 15b?

Correct Answer: (b) 11
Solution:

4. Let x + 2y + 1 = 0 and 2x + 3y + 4 = 0 are two lines of regression computed from some bivariate data. If θ is the acute angle between them, then what is the value of 488 tan 3θ?

Correct Answer: (a) 191
Solution:

5. If two random variables X and Y are connected by relation 2x - 3y/5x + 4y = 4 and X follows Binomial distribution with parameters n = 10 and p = 1/2 then what is the variance of Y?

Correct Answer: (a) 810/361
Solution:

6. If a, b, c are in HP, then what is 1/b - a + 1/b - c equal to?

(A) 2/b

(B) 1/a + 1/c

c) 1/2 (1/a + 1/b + 1/c)

Select the correct answer using the code given below:

Correct Answer: a

7. An edible oil is sold at the rates 150, 200, 250, 300 rupees per litre in four consecutive years. Assuming that an equal amount of money is spent on oil by a family in every year during these years, what is the average price of oil in rupees (approximately) per litre?

Correct Answer: (a) 210
Solution:

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

Correct Answer: (b) 1/4
Solution:

9. Let m =77ⁿ 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?

Correct Answer: (c) 1/4
Solution:

10. 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?

Correct Answer: (c) 1/65
Solution: