Series – Railway Reasoning part – 8

Total Questions: 50

11. A, A, B, D, ? [RRB NTPC 21/01/2021 (Morning)]

Correct Answer: (c) G
Solution:

12. 12496, 12448, 12424,? [RRB NTPC 21/01/2021 (Morning)]

Correct Answer: (d) 12412
Solution:

13. 4 : 9, 25 : 49, ? , 289 : 361 [RRB NTPC 21/01/2021 (Morning)]

Correct Answer: (c) 121 : 169
Solution:

So the required ratio = 121 : 169

14. A1, B27, C125, ? [RRB NTPC 21/01/2021 (Evening)]

Correct Answer: (b) D343
Solution:

Logic -
A + 1 = B , B + 1 = C , C +1 = D
1³ = 1 , 3³ = 27 , 5³ = 125 ,7³ = 343
(cube of odd numbers )

 

15. A, D , I, ?, Y [RRB NTPC 21/01/2021 (Evening)]

Correct Answer: (c) P
Solution:

Logic - addition with odd numbers
A + 3 = D , D + 5 = I , I + 7= P , P + 9 = Y

16. 2, 0, 10, 2, 30, 6, 68, 12, ? , ? [RRB NTPC 21/01/2021 (Evening)]

Correct Answer: (c) 130 ; 20
Solution:

Logic - alternate series
2, 0, 10, 2, 30, 6, 68, 12, ? , ?
1³ + 1 = 2
2³ + 2 = 8 + 2 = 10
3³ + 3 = 27 + 3 = 30
4³ + 4 = 64 + 4 = 68
5³ + 5 = 125 + 5 = 130
And
0 + 2 = 2 , 2 + 4 = 6 , 6 + 6 = 12 , 12 + 8 = 20

17. 44, 37, 29, ?. [RRB NTPC 22/01/2021 (Morning)]

Correct Answer: (b) 20
Solution:

44 − 37 = 7
37 − 29 = 8
29 − x = 9 x = 20

18. 1,12,124,1248,12496, ?. [RRB NTPC 22/01/2021 (Morning)]

Correct Answer: (c) 124972
Solution:

Logic → (previous number is multiplied by 10 + unit digit multiply with 2) 12496 10 + 6 2 = 124972

19. Select the combination of letters that when sequentially placed in the blanks will create a logical pattern. [RRB NTPC 22/01/2021 (Evening)]

abc _ _ dcded _ _ e _ b

Correct Answer: (a) bceaa
Solution:

a b c b c d c d e d e a e a b

20. Select the correct option that can fill the blank in the below series. [RRB NTPC 22/01/2021 (Evening)]

96, 86, 106, 76, ___, 106, 56, 46, 106,

Correct Answer: (d) 66
Solution:

96, 86, 106, 76, ___, 106, 56, 46, 106
Logic :
96 ₋ 86 = 10
76 ₋ 66 = 10
56 ₋ 46 = 10