Missing Number – Railway Reasoning part – 1

Total Questions: 50

1. Find the missing number to complete the following sequence: [NTPC CBT II Level 6 (09/05/2022) Shift 1]

11, 8, 5, 9 = 43
12, 9, 7, 6 = 66
14, 13, 9, 10 = ?

Correct Answer: (a) 92
Solution:

For first row : (11 x 8) - (5 x 9) = 88 - 45 = 43
For second row : (12 x 9) - (7 x 6) = 108 - 42 = 66
Similarly, for third row : (14 x 13) - (9 x 10) = 182 - 90 = 92

2. Find the missing number to complete the following sequence: [NTPC CBT II Level 2 (13/06/2022) Shift 1]

5 , 3 = 9
8, 7 , 4 = 279
9 , 5 = ?

Correct Answer: (b) 604
Solution:

5³ - 3³ = 98
7³ - 4³ = 279
Similarly,
9³ - 5³ = 604

3. Find the missing number to complete the following sequence: [NTPC CBT II Level 2 (13/06/2022) Shift 2]

4, 3, 2 = 21
5, 6, 3 = 52
5, 8, 4 = ?

Correct Answer: (c) 73
Solution:

4, 3, 2 = 21
4² + 3² - 2² = 21
5, 6, 3 = 52
5² + 6² - 3² = 52
Similarly,
5, 8, 4 = ?
5² + 8² - 4² = 73

4. Find the missing number to complete the following sequence: [NTPC CBT II Level 2 (16/06/2022) Shift 3]

12, 4, 37, 25, = 4
2, 36, 87, 51, = 2
18, 3, 58, 49, = ?

Correct Answer: (c) 6
Solution:

Logic:- Find the difference between first two numbers and last two numbers then again find difference between them.
(12, 4, 37, 25),
⇒ {(37 - 25) - (12 - 4)} = 4
(2, 36, 87, 51),
⇒ {(87 - 51) - (36 - 2)} = 2
Similarly,
(18, 3, 58, 49), {(18 - 3) - (58 - 49)} = 6

5. Find the missing number to complete the following sequence: [NTPC CBT - I 28/12/2020 (Morning)]

Correct Answer: (c) 144
Solution:

Here, the pattern that is followed is:
5¹ + 6² + 7³ = 384
4¹ + 5² + 6³ = 245
Similarly,
3¹ + 4² + 5³ = 144

6. Find the missing number to complete the following sequence: [NTPC CBT - I 28/12/2020 (Evening)]

Correct Answer: (c) 16
Solution:

In the above table the pattern is:
For the second column,
⇒ (12 + 8) = (6 + 14) = 20,
For the third column,
⇒ (10 + 6) = (4 + 12) = 16,
For the fourth column,
⇒ (8 + 4) = (2 + 10) = 12,
Similarly, for the first column,
⇒ (14 + 10) = (8 + x) = 24, ⇒ x = 16

7. If 8 + 5 = 1340 is true, then 4 + 6 = ? [NTPC CBT - I 29/12/2020 (Evening)]

Correct Answer: (d) 1024
Solution:

8. If 15 x 71 = 84, 92 x 23 = 57, 37 x 44 = 84, then 54 x 32 = ? [NTPC CBT - I 30/12/2020 (Evening)]

Correct Answer: (b) 51
Solution:

From the above diagram we can say,
15 x 71 = 84, 92 x 23 = 57, 37 x 44 = 84,
So, 54 x 32 = (5 - 4) (3 + 2) = 51

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

Correct Answer: (b) 32
Solution:

20 + 16 + 33 = 69
27 + 19 + 23 = 69
22 + 32 + 15 = 69

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

Correct Answer: (c) 8
Solution:

10 x 8 = 80, 9 x 7 = 63, 8 x 6 = 48,
OR
10 x 8 + 0 = 80, 10 x 6 + 3 = 63, 10 x 4 + 8 = 48