Missing Number – Railway Reasoning part – 1

Total Questions: 50

11. Find the missing number to complete the following sequence: [NTPC CBT - I 04/01/2021 (Evening)]

Correct Answer: (d) 41
Solution:

9 + 8 = 17
17 + 8 = 25 , 25 + 16 = 41
41 + 8 = 49 , 49 + 8 = 57

12. Find the missing number to complete the following sequence: [NTPC CBT - I 08/01/2021 (Evening)]

Correct Answer: (d) 6
Solution:

8 + 4 + 2 + 12 = 26 ÷ 2 = 13
16 + 8 + 4 + 24 = 52 ÷ 2 = 26
14 + 6 + 2 + 22 = 44 ÷ 2 = 22

13. Find the missing number to complete the following sequence: [NTPC CBT - I 08/01/2021 (Evening)]

Correct Answer: (d) 5
Solution:

40 - (22 - 12) = 30
34 - ( 10 - 16) = 40
28 - ( 5 - 20 ) = 43

14. Find the missing number to complete the following sequence: [NTPC CBT - I 12/01/2021 (Evening)]

Correct Answer: (a) 6
Solution:

In 1st: - 1 + 1+ 1 = 2 +1 = 3
In 3rd: - 2 + 8+ 5 = 6 + 9 = 15
In 2nd: - 3 + 9 + 6 = 8 + 10 = 18

15. Find the missing number to complete the following sequence: [NTPC CBT - I 22/01/2021 (Morning)]

Correct Answer: (c) 910
Solution:

Logic :- Consecutive number series
So we get,
12, 34, 56, 78, 910 , 1112

16. Find the missing number to complete the following sequence: [NTPC CBT - I 22/01/2021 (Morning)]

Correct Answer: (c) 9
Solution:

Logic : in each row the middle term is the square of the sum of the digits of the product of the other two.
So, 3 × 4 = 12, 1 + 2 = 3 and 3² = 9

17. In the above table, which two numbers will replace alphabets A and B respectively. [NTPC CBT - I 22/01/2021 (Evening)]

Correct Answer: (b) 49 and 392
Solution:

Pattern-
1st Row - 9 x 3 = 27, 9 x 4 = 36
2nd Row - 16 x 4 = 64, 16 x 5 = 80
Similarly, 3rd Row - A x 7 = 343 ⇒ A = 49
So that, B = 49 x 8 = 392

18. Find the missing number to complete the following sequence: [NTPC CBT - I 22/01/2021 (Evening)]

Correct Answer: (c) 3
Solution:

Logic :
58 + 62 + 23 + 53 = 196
So, the missing number is 3.

19. Find the missing number to complete the following sequence: [NTPC CBT - I 23/01/2021 (Morning)]

24 $ 34 = 68
31 $ 26 = 67
17 $ 52 = ?

Correct Answer: (b) 59
Solution:

Logic : 24 $ 34 = 68
⇒ 2 × 3 = 6 and 4 + 4 = 8 ⇒ 68
31 $ 26 = 67
⇒ 3 × 2 = 6 and 1 + 6 = 7 ⇒ 67
17 $ 52 = ?
⇒ 1 × 5 = 5 and 7 + 2 = 9 ⇒ 59

20. Find the missing number to complete the following sequence: [NTPC CBT - I 25/01/2021 (Evening)]

Correct Answer: (d) 35
Solution:

In first figure , (1 + 5 ) + (1+ 8) +( 4 + 0) =19
In 2nd figure , (2 + 2) + (4 + 1) + ( 5 +7) = 21
In 3rd figure , (4 + 5) + (8 + 7) + (2 + 9) = 35