What sum (in ₹) will earn a simple interest of ₹600 in 2 years at 4% per year rate of interest?

Appeared in: DSSSB 13 August 2024

Explanation

The problem requires finding the Principal (P) given the Simple Interest (SI), Rate (R), and Time (T).
The standard formula for simple interest is SI = (P × R × T) / 100.
To solve for the Principal, the formula is rearranged to P = (SI × 100) / (R × T).
Substituting the given values: P = (600 × 100) / (4 × 2) = 60000 / 8 = ₹7500.

Option A: A principal of ₹10,000 would generate ₹800 in simple interest ((10000 × 4 × 2) / 100), which is more than the ₹600 specified in the question.
Option B: A principal of ₹15,000 would generate ₹1200 in simple interest ((15000 × 4 × 2) / 100), which is double the amount specified.
Option D: A principal of ₹3,750 would generate only ₹300 in simple interest ((3750 × 4 × 2) / 100), which is half the amount required.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Calculation of Principal using the Simple Interest formula as background academic context rather than a clinical decision trigger.
While this is a general mathematics question, mathematical proficiency is a fundamental skill for nurses to ensure patient safety.
Nurses frequently use similar formula rearrangements for critical calculations, such as determining medication dosages, calculating IV drip rates, and converting units (e.g., lbs to kg).
Precision is key; a miscalculation can have serious consequences for patient outcomes.

How to Approach the Question

First, identify all the given components in the problem: Simple Interest (SI = ₹600), Time (T = 2 years), and Rate (R = 4%).
Recognize that the question asks for the 'sum', which is the Principal (P).
Recall the formula for Simple Interest: SI = (P × R × T) / 100.
Rearrange the formula algebraically to isolate the variable you need to find: P = (SI × 100) / (R × T).
Substitute the known values into the rearranged formula and perform the calculation.
Finally, check your answer against the given options to confirm.

Concept Tested & Keywords

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Practise the full DSSSB 13 August 2024

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