If 25% of a number is 50, what is the number?

Appeared in: AIIMS Delhi NO- 2019

Explanation

The question requires finding a whole number when a specific part (25%) of it is given as 50.
This relationship can be expressed as an algebraic equation: 0.25 * x = 50, where 'x' is the unknown number.
To solve for 'x', you can either divide 50 by the decimal 0.25 or multiply 50 by 4 (since 25% is equivalent to the fraction 1/4).
Both calculations, 50 / 0.25 and 50 * 4, result in 200.

Option A: 25% of 100 is 25, not 50. This option confuses the percentage value with the resulting value.
Option B: 25% of 150 (which is 1/4 of 150) equals 37.5, not 50.
Option D: 25% of 250 (which is 1/4 of 250) equals 62.5, not 50.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Solving basic percentage word problems as background academic context rather than a clinical decision trigger.
Percentage calculations are a fundamental skill in nursing, essential for patient safety and effective care.
Nurses use percentages daily for tasks such as calculating medication dosages, preparing solutions with specific concentrations (e.g., a 2% lidocaine solution), determining IV fluid rates, and interpreting nutritional information.
An error in percentage calculation can lead to significant medication errors, either underdosing or overdosing a patient, with potentially severe consequences.

How to Approach the Question

First, identify the core task: you need to find a total amount (a 'number') when a percentage (25%) and its corresponding value (50) are given.
Translate the sentence into a mathematical equation. Let 'x' be the unknown number. The phrase '25% of a number is 50' becomes 0.25 * x = 50.
To make the calculation easier, convert the percentage to a form you are comfortable with, either a decimal (0.25) or a fraction (1/4).
Isolate the variable 'x' to solve the equation. If you used the decimal, divide both sides by 0.25. If you used the fraction, multiply both sides by 4.
Perform the calculation: x = 50 / 0.25 or x = 50 * 4. Both will give you 200.
Finally, quickly check your answer by plugging it back into the original statement: Is 25% of 200 equal to 50? Yes, 0.25 * 200 = 50. This confirms your answer is correct.

Concept Tested & Keywords

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