NDA/NA SOLVED PAPER 2015-II (MATHEMATICS)

Total Questions: 120

31. If the coefficients of xʳ and xʳ⁺¹ are equal in the expansion, then r is equal to

Consider the expansion of (1 + x)²ⁿ⁺¹

Correct Answer: (a) n
Solution:

32. The average of the coefficients of the two middle terms in the expansion is

Consider the expansion of (1 + x)²ⁿ⁺¹

Correct Answer: (b) ²ⁿ⁺¹Cₙ
Solution:

33. The sum of the coefficients of all the terms in the expansion is

Consider the expansion of (1 + x)²ⁿ⁺¹

Correct Answer: (c) 2 × 4ⁿ
Solution:

34. The nth term of an AP. is (3+n)/4 then the sum of first 105 terms is

Correct Answer: (d) 1470
Solution:

35. A polygon has 44 diagonals. The number of its sides is

Correct Answer: (a) 11
Solution:

36. If p, q, r are in one geometric progression and a, b, c are in another geometric progression, then ap, bq, cr are in

Correct Answer: (b) Geometric progression
Solution:

37. The sides of the triangle are in

Correct Answer: (b) A.P.
Solution:


38. sin A, sin B, sin C are in

Correct Answer: (b) A.P.

39. Solve the following equation


1. The value of p × r is 2.
2. p, q and rare in G.P.

Select the correct answer using the code given below :

Correct Answer: (b) 2 only
Solution:


40. The number of ways in which 3 holiday tickets can be given to 20 employees of an organization if each employee is eligible for any one or more of the tickets, is

Correct Answer: (d) 8000
Solution:∴ Each employee is eligible for 1 or more of the tickets.
∴ No. of ways = 20 × 20 × 20 = 8000