Mathematical Operations – Railway Reasoning (part – 1)

Total Questions: 50

21. What will come in place of the question mark (?) in the following equation, if ‘+’ and ‘-’ are interchanged and also ‘×’ and ‘÷’ are interchanged? [Group - D 18/08/2022 (Afternoon)]

8 - 13 + 18 ÷ 9 × 3 = ?

Correct Answer: (a) -33
Solution:

8 - 13 + 18 ÷ 9 × 3 = ?
After interchanging signs according to question,
8 + 13 - 18 × 9 ÷ 3
⇒ 21 - 54 = - 33

22. If ‘+’ means ‘-’, ‘-’ means ‘÷’, ‘÷’ means ‘×’ and ‘×’ means ‘+’, what will come in place of the question mark (?) in the following equation? [Group - D 18/08/2022 (Evening)]

18 - 3 × 14 ÷ 2 + 12 = ?

Correct Answer: (c) 22
Solution:

18 - 3 × 14 ÷ 2 + 12 = ?
After changing signs according to question,
=18 ÷ 3 + 14 × 2 - 12 = 6 + 28 - 12 = 22

23. If ‘+’ means ‘×’, ‘×’ means ‘÷’, ‘÷’ means ‘-’, ‘-’ means ‘+’, what will come in place of the question mark (?) in the following equation? [Group - D 18/08/2022 (Evening)]

13 - 17 + 24 ÷ 54 × 18 + 28 × 14 = ?

Correct Answer: (d) 415
Solution:

13 - 17 + 24 ÷ 54 × 18 + 28 × 14 = ?
On interchanging the signs as per given instructions, we get
13 + 17 × 24 - 54 ÷ 18 × 28 ÷ 14
= 13 + 17 × 24 - 3 × 2 = 13 + 408 - 6 = 415

24. If ‘+’ means ‘÷’, ‘-’ means ‘×’, ‘×’ means ‘+’, ‘÷’ means ‘-’, what will come in place of the question mark (?) in the following equation? [Group - D 18/08/2022 (Evening)]

9 × 8 + 4 - 8 ÷ 5 = ?

Correct Answer: (d) 20
Solution:

9 × 8 + 4 - 8 ÷ 5
After changing signs according to question,
= 9 + 8 ÷ 4 × 8 - 5 = 9 + 16 - 5 = 20

25. What will come in place of the question mark (?) in the following equation, if ‘+’ is interchanged with ‘-’ and ‘÷’ is interchanged with ‘×’? [Group - D 22/08/2022 (Morning)]

7 × 7 ÷ 8 - 12 × 6 + 17 - 14 ÷ 100 = ?

Correct Answer: (d) 107
Solution:

According to the question,
7 × 7 ÷ 8 - 12 × 6 + 17 - 14 ÷ 100 = ?
After interchanging signs according to question,
7 ÷ 7 × 8 + 12 ÷ 6 - 17 + 14 + 100
⇒ 8 + 2 - 17 + 14 + 100 = 107

26. Which two signs should be interchanged to make the given equation correct? [Group - D 22/08/2022 (Morning)]

28 - 28 ÷ 14 + 7 × 2 = 16

Correct Answer: (d) + and -
Solution:

28 - 28 ÷ 14 + 7 × 2 = 16
On interchanging the signs by putting options one by one, we got
28 + 28 ÷ 14 - 7 × 2 ⇒ 28 + 2 - 14 = 16

27. Which of the following interchanges of signs would make the given equation correct? [Group - D 22/08/2022 (Evening)]

5 × 4 ÷ 10 - 8 + 2 = 8

Correct Answer: (a) +, -
Solution:

5 × 4 ÷ 10 - 8 + 2 = 8
On interchanging the signs according to the options one by one, option (a)
satisfies the equation as :
5 × 4 ÷ 10 + 8 - 2 = 8 ⇒ 2 + 8 - 2 = 8

28. What will come in place of the question mark (?) in the following equation if ‘+’ and ‘÷’ are interchanged and also ‘×’ and ‘-’ are interchanged? 42 + 7 ÷ 24 × 6 - 3 = ? [Group - D 22/08/2022 (Evening)]

Correct Answer: (b) 12
Solution:

42 + 7 ÷ 24 × 6 - 3 = ?
If ‘+’ and ‘÷’ are interchanged and also ‘×’ and ‘-’ are interchanged, then
42 ÷ 7 + 24 - 6 × 3 = 6 + 24 - 18 = 12

29. Which two signs should be interchanged to make the given equation correct? [Group - D 23/08/2022 (Morning)]

24 × 6 – 12 + 18 ÷ 3 = 46

Correct Answer: (b) × and ÷
Solution:

24 × 6 – 12 + 18 ÷ 3 = 46
On putting the options one by one, we found that option (b) is satisfying the equation.
Therefore, interchanging × and ÷
24 ÷ 6 – 12 + 18 × 3
= 4 - 12 + 54 = 46

30. If ‘+’ stands for ‘-’, ‘-’ stands for ‘÷’, ‘÷’ stands for ‘×’, and ‘×’ stands for ‘+’, then what will replace ‘?’ in the following equation? [Group - D 23/08/2022 (Evening)]

64 + 32 - 8 × 11 ÷ 3 = ?

Correct Answer: (a) 93
Solution:

Given equation:
64 + 32 - 8 × 11 ÷ 3 = ?
After interchanging the signs as per the question, we get
64 - 32 ÷ 8 + 11 × 3 = ?
64 - 4 + 33 = ? ⇒ 60 + 33 = 93