If the salary of Ravi is 20% less than the salary of Reeta, then how much per cent salary of Reeta is more than the salary of Ravi?

Appeared in: UPUMS Nsg officer-2023

Explanation

The core concept is that percentages are not reversible because the base value for the calculation changes.
Let Reeta's salary be 100. Ravi's salary is 20% less, making it 100 - 20 = 80.
The question asks to find the percentage increase from Ravi's salary (80) to Reeta's salary (100).
The difference is 20. The percentage increase is calculated on the base of Ravi's salary.
Calculation: (Difference / Ravi's Salary) × 100 = (20 / 80) × 100 = 25%.

Option A: This is a common trap. 20% is the percentage decrease from Reeta's salary to Ravi's. The reverse percentage (increase from Ravi's to Reeta's) will be different because the base is smaller (80 instead of 100).
Option B: This is a calculation error. It does not correspond to the correct formula or logical steps for solving this type of percentage problem.
Option D: This is also a calculation error. It is an incorrect value derived from miscalculation.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Percentage change and base value comparison in quantitative aptitude as background academic context rather than a clinical decision trigger.
This question tests fundamental quantitative aptitude, a key skill for nursing and other fields that require data interpretation and calculations (e.g., drug dosage, fluid balance).
Understanding the concept of a changing base is crucial for interpreting statistics and research findings accurately.
What if Ravi's salary was 10% less than Reeta's? The calculation would be (10 / (100 - 10)) × 100 = (10 / 90) × 100 = 11.11%. This shows the formula's application in different scenarios.

How to Approach the Question

Step 1: Identify the initial value and the percentage change. Here, the initial value is Reeta's salary, and the change is a 20% decrease.
Step 2: Assume a simple number for the initial value to make calculations easy. Let Reeta's salary be 100.
Step 3: Calculate the new value after the percentage change. Ravi's salary = 100 - (20% of 100) = 80.
Step 4: Read the second part of the question carefully. It asks for the percentage by which the new value (Reeta's salary) is more than the original value (Ravi's salary). The base for this calculation is now Ravi's salary (80).
Step 5: Calculate the difference between the two values: 100 - 80 = 20.
Step 6: Use the formula for percentage increase: (Difference / New Base) × 100. This gives (20 / 80) × 100 = 25%.

Concept Tested & Keywords

Concept Tested: Percentage change and base value comparison in quantitative aptitude.
Stem keywords: salary, less than, more than, per cent
Lead-in keywords: how much per cent
Negative lead-in flag: false

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