Compound Interest with Mixed Time — 2 years + 73 days at 6 1/4% p.a.: Find the compound interest on ₹ 20480 at 6 1/4% per annum for 2 years and 73 days (assume 365-day year and annual compounding with simple interest on the fractional year).

Introduction / Context:
When interest is compounded annually and the time contains whole years plus a fractional part (days), the standard convention is to compound for the whole years, then apply simple interest on the amount for the fractional remainder at the same annual rate (using fraction of a year). This avoids “partial compounding periods.”

Given Data / Assumptions:

• P = ₹ 20480
• r = 6 1/4% = 6.25% = 0.0625
• Time = 2 years + 73 days; take 73/365 = 0.2 year
• Annual compounding; SI on fractional part

Concept / Approach:
Step 1: Compound for 2 whole years: A2 = P(1 + r)^2. Step 2: For the remaining 0.2 year, add simple interest on A2: extra = A2 * r * 0.2. Total amount = A2 + extra. CI equals total amount minus principal.

Step-by-Step Solution:

Verification / Alternative check:

Why Other Options Are Wrong:

• ₹ 3000, ₹ 3131, ₹ 3636, ₹ 2880 do not match the mixed-period calculation.

Common Pitfalls:

• Compounding the 73-day portion instead of using simple interest after annual periods.
• Using a 360-day year; the question implies 365 days by specifying 73 days explicitly.

Final Answer:
Rs. 2929.