Simple Interest – Find the rate from total interest paid: Ashok borrowed Rs 15,000 for 3 years at simple interest. If the total interest paid is Rs 2,700, find the annual rate of interest (percent per annum).
Aptitude
Simple Interest
Difficulty: Easy
Choose an option
Answer
Correct Answer: 6
Explanation
Introduction / Context:Total interest over a period with known principal and time under SI directly yields the annual rate by rearranging SI = P * r * t.
Given Data / Assumptions:
- P = Rs 15000
- t = 3 years
- SI total = Rs 2700
Concept / Approach:r = SI / (P * t), expressed in percent by multiplying by 100 if needed. Here options are numeric rate values already in percent units.
Step-by-Step Solution:
r = 2700 / (15000 * 3) = 2700 / 45000 = 0.06 = 6Verification / Alternative check:
Annual interest = 15000 * 6% = 900; for 3 years = 2700 (consistent)Why Other Options Are Wrong:
- 18 / 9 / 7.2 / 5.4: do not match computed r.
Common Pitfalls:
- Forgetting to divide by both P and t.
Final Answer:6.