Series – Railway Reasoning part – 11

Total Questions: 50

31. 1, 1, 2, 4, 6, 36, 42, ? [RRB NTPC 14/03/2021 (Evening)]

Correct Answer: (b) 1764
Solution:

1 × 1 = 1
1 + 1 = 2
2 × 2 = 4
4 + 2 = 6
6 × 6 = 36
36 + 6 = 42
42 × 42 = 1764

32. 12, 15, 21, 30, 42, 57, ? [RRB NTPC 14/03/2021 (Evening)]

Correct Answer: (b) 75
Solution:

12 + 3 = 15, 15 + 6 = 21
21 + 9 = 30, 30 + 12 = 42
42 + 15 = 57, 57 + 18 = 75

33. B7E, D11G, F15I, ? [RRB NTPC 14/03/2021 (Evening)]

Correct Answer: (a) H19K
Solution:

B + 2 = D, D+ 2 = F
7 + 4 = 11, 11 + 4 = 15
E + 2 = G, G +2 = I
Next wii be = F + 2 = H, 15 + 4 = 19,
I + 2 = K
⇒ H19K

34. Select the option that will fill in the blank and complete the given series. [RRB NTPC 15/03/2021 (Morning)]

A9B, B125C, C49D, D729E, ____

Correct Answer: (c) E121
Solution:

A + 1 = B , B + 1 = C, C + 1 = D , D + 1 = E
3² = 9 , 5³ = 125 , 7² = 49 , 9³ = 729 , 11² = 121
B + 1 = C, C + 1 = D , D + 1 = E , E + 1 = F

35. 4, 27, 16, 125, ? [RRB NTPC 15/03/2021 (Morning)]

Correct Answer: (c) 36
Solution:

Logic - 2² = 4 , 3³ = 27, 4² = 16 , 5³ = 125 , 6² = 36

36. Select the option that will fill in the blank and complete the given series. [RRB NTPC 15/03/2021 (Morning)]

MU, KS, IQ, GO ,__

Correct Answer: (d) EM
Solution:

Logic - subtract 2 from each alphabet.
M - 2 = K , K -2 = I , I - 2 = G , G - 2 = E
U -2 = S , S - 2 = Q , Q - 2 = O , O - 2 = M
So, EM will complete the given series.

37. 2, 4, 3 , 3, 9, 6, 4, 16, ?, 5, 25,15 [RRB NTPC 15/03/2021 (Morning)]

Correct Answer: (b) 10
Solution:

2,4,3 / 3, 9,6 / 4, 16,? / 5, 25, 15
Firstly arrange in 4 part with 3 numbers
In this part = 2 × 2 (ist digit ) = 4 ( 2nd digit ) ,
Similarly , 4 × 4 = 16 ,

38. 2, 3, 5, 7, 11,13, 17, ?, ? [RRB NTPC 15/03/2021 (Evening)]

Correct Answer: (b) 19, 2
Solution:

consecutive prime number are given, so the next two number are
19, 23

39. A4C, D9G, I16M, P25U, ? [RRB NTPC 15/03/2021 (Evening) ]

Correct Answer: (c) Y36E
Solution:

Logic :-
A + 3 = D, D + 5 = I, I + 7 = P
Square of consecutive numbers
C + 4 = G, G + 6 = M, M + 8 = U
Next term = P + 9 = Y, 6² = 36,
U + 10 = E ⇒ Y36E

40. 1, 1, 1, 2, 4, 8, 3, 9, 27, 4, 16, ? [RRB NTPC 15/03/2021 (Evening)]

Correct Answer: (c) 64
Solution:

1, 1¹, 1², 2, 2², 2³, 3, 3², 3³, 4, 4², 4³ 4³ = 64