Mathematical Operations – Railway Reasoning (part – 1)

Total Questions: 50

31. Which two numbers should be interchanged to make the given equation correct? [Group - D 24/08/2022 (Morning)]

11 + 13 × 3 - 14 ÷ 7 = 44

Correct Answer: (a) 11 and 13
Solution:

11 + 13 × 3 - 14 ÷ 7 = 44
On putting options one by one we found, option (a) is satisfying the equation.
13 + 11 × 3 - 14 ÷ 7 = 44
⇒ 13 + 33 - 2 = 44 ⇒ 46 - 2 = 44

32. If ‘+’ stands for ‘-’, ‘-’ stands for ‘=’, ‘=’ stands for ‘×’, and ‘×’ stands for ‘+’, then what value will come in place of the question mark (?) in the following equation? [Group - D 24/08/2022 (Afternoon)]

24 - 3 × 12 + 4 ÷ 3 = ?

Correct Answer: (b) 8
Solution:

24 - 3 × 12 + 4 ÷ 3
After interchanging the symbols,
24 ÷ 3 + 12 - 4 × 3 = 8 + 12 - 12 = 8

33. If ‘+’ means ‘-’, ‘-’ means ‘×’, ‘×’ means ‘÷’ and ‘÷’ means ‘+’, what will come in place of the question mark (?) in the following equation? [Group - D 25/08/2022 (Afternoon)]

28 - 2 + 80 × 5 ÷ 14 = ?

Correct Answer: (a) 54
Solution:

28 - 2 + 80 × 5 ÷ 14 = ?
After replacing the signs we get,
28 × 2 - 80 ÷ 5 + 14 = 54

34. if ‘+’ means ‘÷’, ‘-’ means ‘×’, ‘×’ means ‘+’, ‘÷’ means ‘-’, what will come in place of the question mark (?) in the following equation? [Group - D 26/08/2022 (Morning)]

9 ÷ 3 × 21 + 7 - 17 = ?

Correct Answer: (c) 57
Solution:

9 ÷ 3 × 21 + 7 – 17 = ?
After changing the signs, we get,
= 9 – 3 + 21 ÷ 7 × 17 = 57

35. By interchanging the positions of which two signs in the given equation, the equation will become balanced? [Group - D 26/08/2022 (Afternoon)]

[{(102 + 42) - (4 × 3)} ÷ (2 - 4)] × 3 = 36

Correct Answer: (b) -, +
Solution:

Given expression :
[{( 102 + 42) - (4 × 3)} ÷ (2 - 4)] × 3 = 36
Check each option one by one, we find that option (b) satisfies the equation.
[{( 102 - 42) + (4 × 3)} ÷ (2 + 4)] × 3 = 36
⇒ [(60 + 12) ÷ 6] × 3 = 36 ⇒ [72 ÷ 6] × 3
= 36 ⇒ 12 × 3 = 36 ⇒ 36 = 36

36. If the places of ‘+’ and ‘-’ are interchanged in the following equation, and also the places of ‘×’ and ‘÷’ are interchanged, then what value will come in place of the question mark (?) in the equation? [Group - D 26/08/2022 (Afternoon)]

49 - 4 ÷ 120 × 8 + 100 =?

Correct Answer: (d) 9
Solution:

Given expression :
49 - 4 ÷ 120 × 8 + 100
After interchanging signs
49 + 4 × 120 ÷ 8 - 100 = 109 - 100 = 9

37. If the places of ‘+’ and ‘-’ are interchanged in the following equation, and also the places of ‘×’ and ‘÷’ are interchanged, then what value will come in place of the question mark (?) in the equation [Group - D 26/08/2022 (Evening)]

10 + 152 × 19 - 2 ÷ 3 = ?

Correct Answer: (a) 8
Solution:

10 + 152 × 19 - 2 ÷ 3
On interchanging the symbols as directed in the question,
10 - 152 ÷ 19 + 2 × 3 ⇒ 10 - 8 + 6 = 8

38. Select the correct combination of mathematical signs to sequentially replace the @ signs and balance the following equation. [Group - D 29/08/2022 (Morning)]

28 @7 @ 12 @ 6 @ 8

Correct Answer: (c) ÷, ×, =, ×
Solution:

28 @ 7 @ 12 @ 6 @ 8
After solving all the options, replace @ with the sign of option C sequentially.
28 ÷ 7 × 12 = 6 × 8
4 × 12 = 6 × 8 ⇒ 48 = 48 (Satisfied)

39. Which of the following interchanges of numbers would make the given equation correct ? [Group - D 29/08/2022 (Afternoon)]

2 × 10 ÷ 8 + 6 - 4 = 9

Correct Answer: (d) 2, 4
Solution:

2 × 10 ÷ 8 + 6 - 4
After the interchanging of numbers 2 and 4.
4 × 10 ÷ 8 + 6 - 2
5 + 6 - 2 = 9 (R.H.S) satisfied.

40. If ‘+’ means ‘-’, ‘-’ means ‘×’, ‘×’ means ‘÷’ and ‘÷’ means ‘+’, what will come in place of the question mark (?) in the following equation? [Group - D 30/08/2022 (Morning)]

100 + 136 × 17 - 12 ÷ 6 = ?

Correct Answer: (d) 10
Solution:

In given : 100 + 136 × 17 - 12 ÷ 6
USE BODMAS RULE
100 - 136 ÷ 17 × 12 + 6
100 - 8 × 12 + 6 = 100 - 96 + 6
= 106 - 96 = 10