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Question

If '+' means '÷', '-' means '+', '×' means '-', '÷' means '×', then what will come in place of the question mark (?) in the following equation?

320 + 64 - 18 ÷ 2 × 28 = ?

This question was previously asked in
SSC Stenographer 2023 Previous Year Paper (13-Oct-2023) (Shift 3)
The correct answer is

13

Understanding Operator Changes

This problem requires us to first understand how the mathematical operators in the given expression are redefined. We are provided with a set of rules that change the meaning of the standard arithmetic symbols.

  • The symbol '+' now represents division (÷).
  • The symbol '-' now represents addition (+).
  • The symbol '×' now represents subtraction (-).
  • The symbol '÷' now represents multiplication (×).

Rewriting the Expression

Now, we will take the original expression and substitute the operators according to the rules given:

Original Expression: \(320 + 64 - 18 ÷ 2 × 28 = ?\)

Let's replace the operators:

  • '+' becomes '÷'
  • '-' becomes '+'
  • '÷' becomes '×'
  • '×' becomes '-'

Substituting these into the expression, we get the new expression:

New Expression: \(320 ÷ 64 + 18 × 2 - 28 = ?\)

Solving the Expression using BODMAS/PEMDAS

To solve the new expression, we need to follow the standard order of operations, commonly known as BODMAS or PEMDAS.

  • Brackets (or Parentheses)
  • Orders (or Exponents)
  • Division and Multiplication (from left to right)
  • Addition and Subtraction (from left to right)

Let's apply BODMAS to our new expression: \(320 ÷ 64 + 18 × 2 - 28\)

Step 1: Division

First, perform the division operation:

\(320 ÷ 64 = 5\)

The expression now becomes:

\(5 + 18 × 2 - 28\)

Step 2: Multiplication

Next, perform the multiplication operation:

\(18 × 2 = 36\)

The expression now becomes:

\(5 + 36 - 28\)

Step 3: Addition and Subtraction (from left to right)

Now, perform the addition and subtraction from left to right.

Perform addition first:

\(5 + 36 = 41\)

The expression is now:

\(41 - 28\)

Finally, perform the subtraction:

\(41 - 28 = 13\)

So, the value of the expression is 13.

Step-by-Step Calculation
Step Operation Calculation Remaining Expression
1 Division \(320 ÷ 64 = 5\) \(5 + 18 × 2 - 28\)
2 Multiplication \(18 × 2 = 36\) \(5 + 36 - 28\)
3 Addition \(5 + 36 = 41\) \(41 - 28\)
4 Subtraction \(41 - 28 = 13\) \(13\)

Revision Table: Operator Swapping Basics

Operator Swapping Rules
Original Symbol New Meaning
+ ÷
- +
× -
÷ ×

Additional Information: Order of Operations (BODMAS/PEMDAS)

The order of operations is crucial when evaluating mathematical expressions involving multiple operations. Failing to follow the correct order will lead to an incorrect result.

BODMAS/PEMDAS helps ensure everyone gets the same answer for the same expression. It standardizes the calculation process.

Remember: Division and Multiplication have the same priority and are performed from left to right as they appear in the expression. Similarly, Addition and Subtraction have the same priority and are performed from left to right.

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Similar Questions

  1. If '+' means 'divided by', '-' means 'add', '×' means 'minus' and '÷' means 'multiplied by', then what will be the value of the following expression:

    [{(18 × 16) - (5 ÷ 2)} + (5 - 1)] ÷ 1

  2. Which two symbols from amongst the given options should be interchanged to make the given equation correct?

    (35 – 2) × 3 = (56 × 8 ÷ 3 + 100) × 11

  3. If A denotes ‘+’, B denotes ‘×’, C denotes ‘−’, and D denotes ‘÷’, then what will come in place of ‘?’ in the following equation?

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  4. If ‘÷’ means ‘ + ’, ‘ - ‘ means ‘÷’, ‘×’ means ‘ - ‘, and ‘ + ’ mean ‘×’ then find the value of

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Important Questions from Logical Puzzle

  1. Seven persons P, Q, R, S, T, U and V like different watches namely W1, W2, W3, W4, W5, W6 and W7 (not necessarily in the same order). P and R do not like odd numbered watch. T likes W5. U does not like W2 or W3 or W6 or W7. P likes prime numbered watch. Q likes W4. S likes W2 or W7. Which of the following statement(s) is/are correct ?

    I. S likes W7.

    II. R likes W2.

    III. U likes W1.

    IV. V likes W3.

  2. If ‘+’ means ‘×’, ‘×’ means ‘÷’, ‘÷’ means ‘–’ and ‘–’ means ‘+’, then

    16 + 18 × 3 ÷ 6 = ?

  3. In a certain code language, ‘Today is last match’ is written as ‘Sa Te Mo Pt’, ‘Last king like your team’ is written as ‘De Ra Mo Lo Zs’, ‘Our team won today match’ is written as ‘Te Ra Pt Ae We’. What is the code for ‘Our won is Last’ in that code language?

  4. In a certain code language, ‘LETTER’ is written as ‘ZLZYIO’. What is the code for ‘ACTION’ in that code language?

  5. If A denotes ‘+’, B denotes ‘×’, C denotes ‘-’, and D denotes ‘÷’, then what will come in place of ‘?’ in the following equation?

    34 A 15 B 3 C 11 B 2 A (51 D 17) = ?

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