Mathematical Operations – Railway Reasoning (part – 3)

Total Questions: 50

1. Which two numbers, from among the given options, should be interchanged to make given equation correct? [Group - D 27/09/2022 (Evening)]

21 ÷ 9 + 99 - 81 × 5 = 3

Correct Answer: (b) 21 and 81
Solution:

21 ÷ 9 + 99 - 81 × 5 = 3
By hit and trial method, check options one by one and verify.
Option (b) satisfies the given expression.
81 ÷ 9 + 99 - 21 × 5 = 3
⇒ 9 + 99 - 105 = 3 ⇒ 108 - 105 = 3
⇒ 3 = 3 (L.H.S = R.H.S)

2. If ‘+’ means ‘x’, ‘x’ means ‘÷’, ‘÷’ means ‘-’, ‘-’ means ‘+’, then what will be the value of the given expression? [Group - D 28/09/2022 (Morning)]

93 - 91 × 7 + 8 ÷ 3 = ?

Correct Answer: (b) 194 
Solution:

Given expression:
93 - 91 × 7 + 8 ÷ 3
As per the instruction,
93 + 91 ÷ 7 × 8 - 3
= 93 + 13 × 8 - 3 = 93 + 104 - 3
= 197 - 3 = 194

3. If ‘+’ means ‘÷’, ‘-’ means ‘+’, ‘x’ means ‘-’ and ‘÷’ means ‘x’, what will come in place of the question mark (?) in the following equation? [Group - D 28/09/2022 (Afternoon)]

15 × 6 ÷ 12 + 4 - 5 = ?

Correct Answer: (c) 2 
Solution:

Given expression :
15 × 6 ÷ 12 + 4 - 5
As per the instruction,
15 - 6 × 12 ÷ 4 + 5
= 15 - 6 × 3 + 5 = 15 - 18 + 5 = 2

4. If ‘+’ means ‘-’, ‘-’ means ‘÷’, ‘÷’ means ‘x’, ‘x’ means ‘+’, what will come in place of the question mark (?) in the following equation? [Group - D 28/09/2022 (Afternoon)]

78 × 3 - 2 ÷ 6 + 4 = ?

Correct Answer: (c) 83
Solution:

78 × 3 - 2 ÷ 6 + 4
As per the instruction,
78 + 3 ÷ 2 × 6 - 4
= 78 + 9 - 4 = 78 + 5 = 83

5. Which two numbers from amongst the given options should be interchanged to make the given equation correct? [Group - D 28/09/2022 (Evening)]

87 × 122 − 369 − 13 ÷ 2 = 701

Correct Answer: (b) 122 and 13
Solution:

In this type of question we will check by putting the options
87 × 122 - 369 -13 ÷ 2 =701
From option (b)
L.H.S = 87 × 13 -369 - 122 ÷ 2
1131 - 369 - 61 = 701 = R.H.S
Hence option (b) is the right answer.

6. If '+' means '×', '−' means '÷', '×' means '−' and '÷' means '+', what will come in place of the question mark (?) in the following equation? [Group - D 28/09/2022 (Evening)]

4 × 5 + 3 ÷ 16 − 1 = ?

Correct Answer: (d) 5
Solution:

4 × 5 + 3 ÷ 16 - 1
According to the given instruction after changing the symbol we get,
4 - 5 × 3 + 16 ÷ 1 ⇒ 4 - 15 +16 = 5

7. If '+' means '−', '−' means '×', '×' means '÷', '÷' means '+', what will come in place of the question mark (?) in the following equation? [Group - D 28/09/2022 (Evening)]

25 × 5 ÷ 7 − 10 × 2 = ?

Correct Answer: (d) 40
Solution:

25 × 5 ÷ 7 -10 × 2
According to the given instruction after changing the sign we get,
25 ÷ 5 + 7 × 10 ÷ 2 = 5 + 35 = 40

8. If '+' means '−', '−' means '×', '×' means '÷', '÷' means '+', what will come in place of the question mark (?) in [Group - D 29/09/2022 (Evening)]

15 − 2 ÷ 90 × 9 + 10 = ?

Correct Answer: (d) 30
Solution:

15 - 2 ÷ 90 × 9 + 10 = ?
According to the question,
15 × 2 + 90 ÷ 9 - 10 ⇒ 30 + 10 - 10 = 30

9. Select the correct combination of mathematical signs that can sequentially replace the * and balance the given equation. [Group - D 30/09/2022 (Morning)]

32 * 16 * 8 * 2 * 3 * 5 * 5

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

32 × 16 ÷ 8 × 2 ÷ 3 × 5 × 5
By hit and trial method, go through option (c)
32 - 16 + 8 ÷ 2 = 3 × 5 + 5
⇒ 32 - 16 + 4 = 15 + 5 ⇒ 20 = 20 (satisfy)

10. Which of the following two numbers should be interchanged to make the given equation correct? [Group - D 30/09/2022 (Evening)]

3 × 5 + 20 ÷ 8 − 17 = 11

Correct Answer: (a) 5 and 8
Solution:

3 × 5 + 20 ÷ 8 - 17 = 11
By hit and trial method, go through option (a)
3 × 8 + 20 ÷ 5 − 17 = 11
⇒ 24 + 4 − 17 = 11 ⇒ 11 = 11 (Satisfy)