Which two signs should be interchanged to make the below equation mathematically correct?
(56+6) 8 × 3 + 3 = 18

Appeared in: DSSSB -28 August 2019 (Shift-2)

Explanation

The question requires finding which pair of interchanged signs will correct the given mathematical equation.
The original equation is likely a mistyped version of 56 ÷ 8 × 3 + 3 = 18, which evaluates to the incorrect statement 24 = 18.
Interchanging the = and + signs transforms the equation into 56 ÷ 8 × 3 = 3 + 18.
Following the BODMAS rule, the left side becomes 7 × 3 = 21.
The right side is 3 + 18 = 21.
Since both sides equal 21, the equation becomes correct after this specific interchange.

Option A: The original interpreted equation 56 ÷ 8 × 3 + 3 = 18 only has one plus sign. If we consider the malformed text (56+6) 8 × 3 + 3 = 18, swapping the two plus signs with each other would result in no change to the equation.
Option B: The interpreted equation 56 ÷ 8 × 3 + 3 = 18 does not contain a subtraction sign (−), making it impossible to perform this interchange.
Option C: Similar to the previous option, the interpreted equation 56 ÷ 8 × 3 + 3 = 18 lacks a subtraction sign (−), so this swap cannot be performed.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Mathematical Reasoning and Equation Correction as background academic context rather than a clinical decision trigger.
While not a clinical question, this type of logical reasoning is a foundational skill for nurses.
Nurses use similar systematic, step-by-step problem-solving for tasks like calculating drug dosages, titrating IV drips, and interpreting patient data, where the order of operations is critical for patient safety.
What if the numbers were different, such as in a dosage calculation like (500mg / 250mg) * 5mL? A mistake in the order of operations could lead to a significant medication error. This highlights the importance of mastering procedural thinking.

How to Approach the Question

First, carefully read the equation and identify the numbers and operators. Note any ambiguities or likely transcription errors.
Based on the numbers, form the most logical intended equation. In this case, (56+6) 8 is likely 56 ÷ 8.
Verify if the interpreted equation is correct as it stands by applying the BODMAS rule (Brackets, Orders, Division/Multiplication, Addition/Subtraction).
If the equation is incorrect, begin testing the options. For each option, perform the suggested sign interchange.
After each interchange, re-evaluate both the left-hand side (LHS) and right-hand side (RHS) of the new equation.
The correct answer is the option that results in a balanced equation where LHS equals RHS.

Concept Tested & Keywords

Q2iMjuY5v1oVSVeChSOUm7

Practise the full DSSSB -28 August 2019 (Shift-2)

Attempt every question from this paper in a timed mock, then review the full solution for each one.