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Question

What will come in the place of the question mark (?) in the following equation, if ‘+’ and ‘×’ are interchanged, and ‘−’ and ‘÷’ are interchanged?

2 + 8 ÷ 84 − 7 × 27 = ?

This question was previously asked in
RRB NTPC 2024 CBT 1 Question Paper (28-Aug-2025) (Shift 3)
The correct answer is
31

To solve this problem, we need to first understand the transformations applied to the mathematical operators in the given equation.

The transformations are as follows:

  • '+' is interchanged with '×'
  • '−' is interchanged with '÷'

Now, let's apply these transformations to the given equation:

\(2 + 8 \div 84 - 7 \times 27 = ?\)

After the interchange of operations, the equation becomes:

\(2 \times 8 - 84 \div 7 + 27 = ?\)

Next, we solve the equation by following the order of operations, commonly known as BODMAS/BIDMAS (Brackets, Orders, Division and Multiplication, Addition and Subtraction).

  1. First, perform the multiplication and division:
    • \(2 \times 8 = 16\)
    • \(84 \div 7 = 12\)
  2. Next, replace these results back into the equation:

\(16 - 12 + 27\)

  1. Finally, solve the addition and subtraction from left to right:
    • \(16 - 12 = 4\)
    • \(4 + 27 = 31\)

Therefore, the value that will come in place of the question mark is 31.

Checking with the given options, the correct answer is indeed:

31

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Similar Questions

  1. What will come in the place of the question mark (?) in the following equation, if '+' and '−' are interchanged and '×' and '÷' are interchanged?
    65 × 5 − 19 ÷ 3 + 25 = ?
  2. What will come in place of the question mark (?) in the following equation if '×' and '+' are interchanged and '−' and '÷' are interchanged?
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  3. If 'A' stands for '÷', 'B' stands for '×', 'C' stands for '+' and 'D' stands for '−', what will come in place of the question mark (?) in the following equation?

    7 B 5 D 48 A 4 C 13 = ?
  4. What will come in the place of the question mark (?) in the following equation, if ‘+’ and ‘÷’ are interchanged, and ‘−’ and ‘×’ are interchanged?

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  5. While solving a mathematical problem, Atul squared the initial number and then subtracted $15$ from it. Pratul first subtracted $15$ from the initial number and then squared the difference. If both obtained the same answer, what was the initial number?
  6. Which two signs are to be interchanged to make the given equation correct?

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Important Questions from Mathematical Operations

  1. What will come in the place of ‘?’ in the following equation if ‘+’ and ‘−’ are interchanged and ‘×’ and ‘÷’ are interchanged?
    18 ÷ 9 + 24 × 3 − 16 = ?

  2. If ‘A’ stands for ‘÷’, ‘B’ stands for ‘×’, ‘C’ stands for ‘+’, and ‘D’ stands for ‘−’, what will come in place of the question mark (?) in the following equation?
    88 B 3 D 12 A 4 C 6 = ?

  3. Select the set in which the numbers are related in the same way as are the numbers of the given sets.
    (NOTE: Operations should be performed on whole numbers without breaking down the numbers into their constituent digits. E.g., 13 – Operations on 13 such as adding/subtracting/multiplying, etc., to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)
    Given sets:
    (9, 21, 193)
    (12, 15, 184)

  4. What will come in the place of the question mark (?) in the following equation, if ‘÷’ and ‘+’ are interchanged and ‘−’ and ‘×’ are interchanged?
    44 ÷ 78 + 6 − 3 × 19 = ?

  5. Two sets of numbers are given below. In each set of numbers, certain mathematical operation(s) on the first number result(s) in the second number. Similarly, certain mathematical operation(s) on the second number result(s) in the third number and so on. Which of the given options follows the same set of operations as in the given sets?

    (NOTE: Operations should be performed on the whole numbers, without breaking down the numbers into their constituent digits. E.g. 13 – Operations on 13 such as adding/subtracting/multiplying to 13 can be performed. Breaking down 13 into 1 and 3 and then performing mathematical operations on 1 and 3 is not allowed.)

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