Missing Number – Railway Reasoning part – 1

Total Questions: 50

31. Of the four given equations , the first three are solved on the basis of a certain system, where the function of the ‘ * ’ remains the same. Find the correct answer for the unsolved fourth equation on the same basis. [NTPC CBT - I 05/04/2021 (Morning)]

62 = 9
45 = 12
73 = 14
33 = ?

Correct Answer: (d) 6
Solution:

{6 × (2 + 1)} ÷ 2 = 9
{4 × (5 + 1)} ÷ 2 = 12
{7 × (3 + 1)} ÷ 2 = 14
{3 × (3 + 1)} ÷ 2 = 6
Therefore, option (d) is correct.

32. If 69 - 26 = 66; 86 - 34 = 60 ; 35 - 28 = 31, then 77 - 21 = ? [NTPC CBT - I 07/04/2021 (Evening)]

Correct Answer: (b) 51
Solution:

6 × 9 + 2 × 6 = 66
8 × 6 + 3 × 4 = 60
3 × 5 + 2 × 8 = 31
7 × 7 + 1 × 2 = 51

33. Find the missing number to complete the following sequence: [NTPC CBT - I 08/04/2021 (Evening)]

Correct Answer: (c) 4
Solution:

34. Find the missing number to complete the following sequence: [RRB JE 22/05/2019 (Afternoon)]

Correct Answer: (c) 2
Solution:

IIʳᵈ Row = Addition of digits of Iˢᵗ row → (3 + 2) = 5
IIIʳᵈ Row = subtraction of digits of Iˢᵗ row → (3 - 2) = 1
IVᵗʰ Row = multiplication of digits of Iˢᵗ row  → (3 × 2) = 6

35. Find the missing number to complete the following sequence: [RRB ALP Tier - I 17/08/2018 (Morning)]

Correct Answer: (c) 142
Solution:

101 + 15 = 116 and 43 + 35 = 78
116 - 78 = 38.
Similarly,
184 + 48 = 232 and 56 + 34 = 90
232 - 90 = 142.

36. Find the missing number to complete the following sequence: [RRB ALP Tier - I 20/08/2018 (Afternoon)]

Correct Answer: (d) 16
Solution:

In figure A
Let A = 14, B = 12 and C = 84
Logic:-
(A ÷ 2) × B = C
(14 ÷ 2) × 12 = 84
And ,
In figure B,
Let A = 18 , B= 9 ,C = 81
(18 ÷ 2) × 9 = 81
Similarly, In figure C
Let A = 16, B = 11, C = 88
(16 ÷ 2) × 11 = 88

37. Find the missing number to complete the following sequence: [Level 6 (09/05/2022) Shift 2]

15, 8, 12 = 10
26, 6, 13 = 12
11, 12, 4 = ?

Correct Answer: (b) 33
Solution:

Pattern : 1st number × 2nd number ÷ 3rd number = result
15 × 8 ÷ 12 = 10
26 × 6 ÷ 13 = 12
11 × 12 ÷ 4 = 33

38. Find the missing number to complete the following sequence: [Level 4 (10/05/2022) Shift 1]

12, 33 = 57
10, 28 = 48
14, 39 = ?

Correct Answer: (a) 67
Solution:

1st × 2 + 2nd = Answer
12 × 2 + 33 = 57
10 × 2 + 28 = 48
Similarly,
14 × 2 + 39 = 67

39. Find the missing number to complete the following sequence: [Level 4 (10/05/2022) Shift 1]

8, 35 = 29
10, 48 = 52
12, 57 = ?

Correct Answer: (a) 87
Solution:

8² - 35 = 64 - 35 = 29
10² - 48 = 100 - 48 = 52
Similarly ,
12² - 57 = 87

40. Find the missing number to complete the following sequence: [Level 5 (12/06/2022) Shift 1]

21, 9, 40 = 149
18, 7, 25 = 101
15, 11, 30 = ?

Correct Answer: (d) 135
Solution:

21 × 9 - 40 = 149
18 × 7 - 5 = 121
Similarly,
15 × 11 - 30 = 135