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BANKERS TUTORIAL · RBI · ORIGINAL PRACTICE & ANALYSIS

Practice & review: Real and nominal interest: purchasing-power arithmetic

A nominal interest rate measures a monetary return or borrowing cost, while a real rate adjusts for price changes. Comparing them requires matching the time period and distinguishing expected inflation from inflation realised afterwards.

01 / 03Learn with a clear direction

3 min read Original learning material · Prepared 14 Oct 2026

The worked question on this page is original educational practice. It is not represented as a question from an official previous-year examination paper.

01 / UNDERSTANDING

Review the question

Create an original nominal-versus-real exercise with stated periods and no implied product advice or guaranteed return. Use a case where a positive nominal change leaves a negative real result. An original checkpoint is: What is the exact real gain when the nominal factor is 1.10 and the price factor is 1.05? Supported answer: About 4.76%. Explain the decisive fact, then alter one condition and solve again. This is an original practice method, not a claim that the question appeared in an official past paper.

02 / UNDERSTANDING

The concept in context

Positive nominal returns do not automatically imply positive growth in purchasing power, and this arithmetic is not a product recommendation. A useful study check is to match the rate periods and compounding assumptions, then label expected and realised real rates separately. Explain why the method fits the stated facts before applying it to a changed situation.

03 / UNDERSTANDING

A worked learning case

In a fictional one-period calculation, 100 units become 110 after a 10% nominal return while the price index rises by 5%. The final amount purchases what 110 divided by 1.05, or about 104.76 initial-price units, could buy. The real gain is about 4.76%, slightly below the five-percentage-point subtraction approximation.

ORIGINAL EDUCATIONAL PRACTICE

Try it before you check.

What is the exact real gain when the nominal factor is 1.10 and the price factor is 1.05?

Show the answer and reasoning

About 4.76%.

Dividing 1.10 by 1.05 gives approximately 1.047619. Subtracting one and multiplying by 100 gives a real gain near 4.76%. Simply subtracting 5% from 10% gives a useful small-rate approximation, not the exact compound adjustment. Both rates must refer to the same period for this comparison to be meaningful.

Two traps to watch for.

  • Calling nominal interest an automatic purchasing-power gain.
  • Using inflation and interest rates from different periods.

YOUR TOPIC-SPECIFIC LEARNING MAP

Learn from the attempt

  1. Match the rate periods and compounding assumptions.

  2. Divide the two gross growth factors.

  3. Label expected and realised real rates separately.

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.

  1. www.ncert.nic.in https://www.ncert.nic.in/textbook/pdf/leec103.pdf
  2. ncert.nic.in https://ncert.nic.in/textbook.php?leec1=ps-6

For RBI preparation, check the current official notice before relying on changing dates, rules or examination requirements.

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