Mathematics (NDA SOLVED PAPER 2020 – II) (01 to 50)

Total Questions: 50

41. If A is a matrix of order 3 × 5 and B is a matrix of order 5 × 3, then the order of AB and BA will respectively be

Correct Answer: (c) 3 × 3 and 5 × 5
Solution:

42. If p², q² and r² (where p, q, r > 0) are in GP, then which of the following is/are correct?

1. p, q and r in GP.
2. ln p , ln q and ln r are in AP.
Select the correct answer using the code given below

Correct Answer: (c) Both 1 and 2
Solution:

43. If cot α and cot β are the roots of the equation x²− 3x + 2 = 0, then what is cot (α + β) equal to?

Correct Answer: (b) 1/3
Solution:

44. The roots α and β of a quadratic equation, satisfy the relations α + β = α² + β² and αβ = α²β². What is the number of such quadratic equations?

Correct Answer: (d)
Solution:

45. Solve it?

Correct Answer: (a) 240°
Solution:

46. Solve it?

Correct Answer: (b) 1
Solution:

47. Consider the proper subsets of {1, 2, 3, 4}. How many of these proper subsets are superset of the set {3}?

Correct Answer: (c) 7
Solution:

48. Solve it?

Correct Answer: (a)
Solution:

49. What is the sum of the last five coefficients in the expansion of (1 + x²) when it is expanded in ascending powers of x?

Correct Answer: (a) 256
Solution:

50. Consider the following in respect of a non-singular matrix of order 3.

1. A (adj A) = (adj A) A
2. |adj A| = |A|
Which of the above statements is/are correct?

Correct Answer: (a) 1 Only
Solution: