If the Cost price is Rs. 120 and selling Price is Rs. 90, then find the loss percentage.

Appeared in: RRB Staff Nurse Kolkata-2015

Explanation

The first step is to determine the monetary loss, which is the difference between the Cost Price (CP) and the Selling Price (SP).
Loss = CP - SP = Rs. 120 - Rs. 90 = Rs. 30.
The loss percentage is then calculated by dividing the loss amount by the cost price and multiplying by 100.
Loss Percentage = (Loss / CP) × 100.
Substituting the values: (30 / 120) × 100 = (1/4) × 100 = 25%.

Option A: This value represents the absolute loss amount (Rs. 30), not the loss percentage.
Option C: This is the selling price expressed as a percentage of the cost price (90/120 × 100 = 75%), not the loss percentage.
Option D: This percentage (33.33%) is the result of incorrectly calculating the loss percentage based on the Selling Price instead of the Cost Price ((30 / 90) × 100). Loss percentage must always be calculated on the Cost Price.

Visual 1: Formula Card - A simple card displaying the key formulas for business mathematics: Profit = SP - CP; Loss = CP - SP; Profit % = (Profit/CP) x 100; Loss % = (Loss/CP) x 100.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Loss Percentage in basic arithmetic as background academic context rather than a clinical decision trigger.
While not a clinical question, strong numeracy skills are fundamental for nurses to ensure patient safety.
Nurses use similar percentage calculations daily for tasks like preparing solutions, calculating medication dosages based on weight, and determining IV drip rates.
Accuracy in calculation is non-negotiable in nursing, as a small mathematical error can have significant consequences for patient outcomes.

How to Approach the Question

Step 1: Identify the given values from the question: Cost Price (CP) = Rs. 120 and Selling Price (SP) = Rs. 90.
Step 2: Compare the SP and CP. Since SP is less than CP, it is a loss.
Step 3: Calculate the absolute loss amount using the formula: Loss = CP - SP.
Step 4: Calculate the loss percentage using the formula: Loss % = (Loss / CP) × 100.
Step 5: Crucially, remember that percentage profit or loss is always calculated with the Cost Price as the base (the denominator).
Step 6: Perform the calculation: (30 / 120) * 100, which simplifies to 25%.

Concept Tested & Keywords

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