Difficulty: Medium
Correct Answer: 15% per annum
Explanation:
Introduction / Context:The difference between consecutive-year amounts under SI equals the constant annual interest. Dividing by the principal yields the rate.
Given Data / Assumptions:
Concept / Approach:Annual SI = A3 - A2. Then find P from A2 = P + 2 * (annual SI). Compute r% = (annual SI / P) * 100.
Step-by-Step Solution:
Annual SI = 783 - 702 = Rs 81P = 702 - 2 * 81 = 702 - 162 = Rs 540r% = (81 / 540) * 100 = 15% per annumVerification / Alternative check:
A3 check: 540 + 3 * 81 = 540 + 243 = 783 (matches)Why Other Options Are Wrong:
Common Pitfalls:
Final Answer:15% per annum.
Discussion & Comments