If '+' means '–', '–' means '×', '×' means '÷', '÷' means '+', what will come in place of question mark [?] in the following equation? 231/6 - 155 *2233 + 11 = ?

1. A

   1644

2. B

   1525

3. C

   1452

4. D

   1338

Appeared in: DSSSB 6 September 2024

Explanation

• First, the operators in the equation are substituted according to the given rules: '÷' becomes '+', '–' becomes '×', '×' becomes '÷', and '+' becomes '–'.
• The original equation 231 - 6 ÷ 155 + 2233 × 11 transforms into 231 × 6 + 155 - 2233 ÷ 11.
• The BODMAS rule (Division, Multiplication, Addition, Subtraction) is then applied to the new equation to ensure the correct order of operations.
• Step 1 (Division): 2233 ÷ 11 = 203.
• Step 2 (Multiplication): 231 × 6 = 1386.
• Step 3 (Addition & Subtraction): 1386 + 155 - 203 = 1541 - 203 = 1338.

Why Other Options Were Wrong

• Option A: This result is incorrect. It likely arises from not following the BODMAS order of operations or from a simple arithmetic error during calculation.
• Option B: This is a calculation error. Such errors often occur when the order of operations (BODMAS) is ignored, for example, performing addition before multiplication or division.
• Option C: This result is incorrect. It may be the product of a miscalculation or an incorrect sequence of operations, deviating from the standard BODMAS protocol.

Related Visual

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mathematical Reasoning: Operator Substitution and BODMAS Rule as background academic context rather than a clinical decision trigger.
• While not a clinical question, these reasoning problems test attention to detail and logical, sequential thinking.
• These skills are crucial for nurses in daily practice, especially for tasks like medication dosage calculation, IV drip rate adjustments, and interpreting patient data charts, where precision is vital for patient safety.
• What if the BODMAS rule was ignored and operations were done strictly left-to-right? The answer would be (231 * 6 + 155 - 2233) / 11 = (1386 + 155 - 2233) / 11 = (1541 - 2233) / 11 = -692 / 11 = -62.9, which is incorrect and highlights the importance of the rule.

How to Approach the Question

• Step 1: Carefully read the question to identify the rules for operator substitution. Note down which symbol replaces which.
• Step 2: Rewrite the entire mathematical equation, replacing each original operator with its new meaning as defined by the rules.
• Step 3: Recall the BODMAS rule for the correct order of operations: Brackets, Orders, Division, Multiplication, Addition, Subtraction.
• Step 4: Apply the BODMAS rule to the new equation. Start by solving any division and multiplication operations, moving from left to right.
• Step 5: After completing multiplication and division, perform the addition and subtraction operations, again moving from left to right.
• Step 6: The result of the final calculation is your answer. Compare it with the given options to select the correct one.

Concept Tested & Keywords

• Concept Tested: Mathematical Reasoning: Operator Substitution and BODMAS Rule
• Stem keywords: mathematical equation, operator substitution, BODMAS
• Lead-in keywords: what will come in place of question mark

Question ID

Q0tzV5adfI4JTzj2rUIdLC

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