This Bankers Tutorial article is independent educational material. Examples are illustrative, and changing rules or examination requirements should be checked at the official source.
01 / UNDERSTANDING
Understand the idea
Follow the first few payments on a small hypothetical loan. Showing interest calculated on the declining balance explains why a stable instalment does not mean an unchanged principal share. Show a borrower comparing the original loan amount with the balance after several payments. Splitting each payment visibly helps explain why the amount paid is not identical to principal retired, and why the interest calculation's opening balance matters to the next row of the schedule.
02 / UNDERSTANDING
The concept in context
In a simplified reducing-balance loan, each period's interest is calculated on the outstanding principal under the stated rate convention. The instalment first covers that interest and the remainder reduces principal. The next period begins with a lower balance if all amounts are paid as assumed.
A level payment does not mean that equal principal is repaid in every period. Early payments can contain more interest because the outstanding balance is larger. Actual schedules depend on the contract, payment dates and other applicable terms, so classroom examples should state their simplified assumptions clearly.
03 / UNDERSTANDING
A worked learning case
A teaching loan begins a period with ₹10,000 outstanding, an assumed monthly rate of one per cent and a ₹1,000 payment. Interest is ₹100 and principal reduction is ₹900, leaving ₹9,100 before the next period. The example excludes fees, missed payments and day-count complications to isolate amortisation mechanics.
ORIGINAL EDUCATIONAL PRACTICE
Try it before you check.
In the stated example, how much of the ₹1,000 payment reduces principal?
Show the answer and reasoning
₹900.
Period interest is one per cent of the ₹10,000 opening balance, or ₹100. Subtracting that interest from the ₹1,000 payment leaves ₹900 to reduce principal. The closing balance is therefore ₹9,100 under the simplified assumptions, rather than ₹9,000 or an unchanged ₹10,000 balance.
Two traps to watch for.
- Treating the entire instalment as principal repayment.
- Assuming equal instalments always contain equal amounts of interest.
YOUR TOPIC-SPECIFIC LEARNING MAP
Turn understanding into practice
Calculate interest from the stated opening principal balance.
Split the payment into interest and principal portions.
Carry the closing balance into the next assumed period.
Explain the idea, apply it to a new situation, then check what changed in your reasoning.
BANKERS TUTORIAL · SOURCE NOTES
Keep the source alongside your notes.
Official links provide subject context and authoritative reference material. This guide’s explanation, scenario and question are original Bankers Tutorial learning content.
- iibf.org.in https://iibf.org.in/jaiib-junior-associate-IIBF
- iibf.org.in https://iibf.org.in/documents/RulesSyllabus/2026/FlagshipCourses/21%20-%20JAIIB-Final_Exam_24.07.25_Final_23.02.2026.pdf
- www.rbi.org.in https://www.rbi.org.in/commonperson/English/Scripts/PressReleases.aspx?Id=2123
For JAIIB preparation, check the current official notice before relying on changing dates, rules or examination requirements.
