Compound Interest (Without Using Formula) — ICSE Class 9 Maths Important Questions
13 hand-picked ICSE Class 9 Maths important questions for Compound Interest (Without Using Formula), each with a full model answer — the formats and topics most likely to appear in your board exam.
- 13
- Questions
- 6
- Question types
- 32
- Total marks
- ₹0
- With answers
High-yield ICSE Compound Interest (without formula) questions compute interest year by year: find Year 1 interest on the principal, add it to get the new principal, then repeat for later years. Common tasks are two- and three-year CI, difference between CI and SI, and growth/depreciation problems solved by successive yearly calculation.
About Compound Interest (Without Using Formula)
In the ICSE Class 9 Maths chapter Compound Interest (without using formula) you calculate interest year by year: the amount at the end of each year becomes the principal for the next year. You handle 2-3 year problems, the difference between compound and simple interest, and simple growth and depreciation.
Key concepts & formulas
Interest for a year =P× R× 1/100. Add it to P to get the amount, which becomes the principal for the next year; repeat for each year.
CI=Final Amount-Original Principal, after computing the amount year by year.
Growth adds a percentage each period (new value = value + increase); depreciation subtracts it (new value = value - decrease), computed year by year.
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Important questions with answers
Try each on paper first, then reveal the model answer to check your method.
| Question type | Count | Marks |
|---|---|---|
| MCQ | 4 | 1 |
| Assertion–Reason | 1 | 1 |
| Very Short | 2 | 2 |
| Short Answer | 3 | 3 |
| Long Answer | 2 | 5 |
| Case-based | 1 | 4 |
Multiple-choice questions (1 mark)
The simple interest on Rs 2000 for 1 year at 10\% per annum is:
- (a)
Rs 100
- (b)
Rs 200
- (c)
Rs 220
- (d)
Rs 20
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Answer: (b) Rs 200.
Interest=2000×10×1/100=Rs 200. For the first year, SI and CI are equal.
In the year-by-year method, the amount at the end of the first year becomes the:
- (a)
Interest for the second year
- (b)
Principal for the second year
- (c)
Rate for the second year
- (d)
Compound interest
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Answer: (b) Principal for the second year.
Under compounding, the previous year's amount (principal + interest) is treated as the principal for the next year.
The compound interest on Rs 5000 for 2 years at 10\% per annum is:
- (a)
Rs 1000
- (b)
Rs 1050
- (c)
Rs 1100
- (d)
Rs 500
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Answer: (b) Rs 1050.
Year 1 interest =5000×10/100=500, amount =5500. Year 2 interest =5500×10/100=550. CI =500+550=Rs 1050.
For 2 years at R\% per annum, the difference between CI and SI on a sum P equals:
- (a)
P(R/100)
- (b)
P(R/100)^2
- (c)
2P(R/100)
- (d)
P(R/100)^3
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Answer: (b) P(R/100)^2.
The extra amount in CI is the interest on the first year's interest: interest of PR/100 at R\% is PR/100×R/100=P(R/100)^2.
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Practise free with the AI tutor →Assertion–Reason questions (1 mark)
Assertion (A): For the first year, compound interest and simple interest on the same sum at the same rate are equal.
Reason (R): In the first year there is no interest earned on previous interest.
- (a)
Both A and R are true and R is the correct explanation of A
- (b)
Both A and R are true but R is not the correct explanation of A
- (c)
A is true but R is false
- (d)
A is false but R is true
Show model answer
Answer: (a) Both are true and R correctly explains A. Compounding differs from simple interest only when interest is earned on earlier interest, which first happens in the second year.
Very short answer questions (2 marks)
Find the amount on Rs 8000 for 1 year at 12\% per annum compounded annually.
Show model answer
Interest for year 1 =8000×12×1/100=Rs 960.
Amount =8000+960=Rs 8960.
The population of a town is 6000 and increases by 5\% in one year. Find the population after one year.
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Increase =6000×5/100=300.
Population after 1 year =6000+300=6300.
Short answer questions (3 marks)
Calculate the compound interest on Rs 10000 for 2 years at 8\% per annum, computing year by year.
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Year 1: Interest =10000×8×1/100=Rs 800.
Amount after year 1 =10000+800=Rs 10800 (principal for year 2).
Year 2: Interest =10800×8×1/100=Rs 864.
Amount after year 2 =10800+864=Rs 11664.
CI=11664-10000=Rs 1664.
Find the compound interest on Rs 6250 for 3 years at 8\% per annum.
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Year 1: Interest =6250×8/100=500; amount =6250+500=6750.
Year 2: Interest =6750×8/100=540; amount =6750+540=7290.
Year 3: Interest =7290×8/100=583.20; amount =7290+583.20=7873.20.
CI=7873.20-6250=Rs 1623.20.
The difference between the compound interest and the simple interest on a sum for 2 years at 10\% per annum is Rs 50. Find the sum, using year-by-year working.
Show model answer
Let the sum be Rs P.
Simple interest for 2 years =P×10×2/100=P/5.
Compound interest: Year 1 interest =P×10/100=P/10; amount =P+P/10=11P/10.
Year 2 interest =1/10×11P/10=11P/100. So CI=P/10+11P/100=10P+11P/100=21P/100.
Difference =CI-SI=21P/100-P/5=21P-20P/100=P/100.
Given P/100=50 P=Rs 5000.
Long answer questions (5 marks)
A machine is purchased for Rs 80000. Its value depreciates by 10\% in the first year and by 8\% in the second year. Find its value at the end of 2 years and the total depreciation.
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Year 1 (depreciation 10\%):
Decrease =80000×10/100=Rs 8000.
Value at end of year 1 =80000-8000=Rs 72000.
Year 2 (depreciation 8\%):
Decrease =72000×8/100=Rs 5760.
Value at end of year 2 =72000-5760=Rs 66240.
Total depreciation =80000-66240=Rs 13760.
So the machine is worth Rs 66240 after 2 years, having depreciated by Rs 13760.
A sum of money amounts to Rs 9680 in 2 years and to Rs 10648 in 3 years, compounded annually. Find the sum and the rate of interest, using the year-by-year idea.
Show model answer
The interest for the third year is the difference of the two amounts:
Third-year interest =10648-9680=Rs 968.
This Rs 968 is the interest for one year on the amount after 2 years, i.e. on Rs 9680.
R=968×100/9680×1=10\% per annum.
Finding the sum P: After 2 years the amount is 9680. Working backwards at 10\%:
Amount after year 1 =9680/1.1=Rs 8800.
Sum P=8800/1.1=Rs 8000.
Check: Year 1: 80008800; Year 2: 88009680; Year 3: 968010648. Correct.
Hence the sum is Rs 8000 and the rate is 10\% per annum.
Case-based questions (4 marks)
Rohan deposits Rs 20000 in a bank that pays 10\% per annum compounded annually. He wants to track his money year by year.
(i) Find the interest for the first year.
(ii) Find the amount at the end of the first year.
(iii) Find the interest for the second year.
(iv) Find the compound interest for 2 years.
Show model answer
(i) First-year interest =20000×10×1/100=Rs 2000.
(ii) Amount at end of year 1 =20000+2000=Rs 22000.
(iii) Second-year interest =22000×10×1/100=Rs 2200.
(iv) Amount at end of year 2 =22000+2200=Rs 24200; CI =24200-20000=Rs 4200.
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Yes. All 13 ICSE Class 9 Maths important questions for Compound Interest (Without Using Formula) are free, with full model answers and no login required.Do these Compound Interest (Without Using Formula) questions follow the latest ICSE syllabus?
Yes — they are aligned to the CISCE latest syllabus syllabus for ICSE Class 9 Maths, so nothing here is outside the current course.How should I practise the Compound Interest (Without Using Formula) important questions?
Attempt each question on paper first, then reveal the model answer to check your method — not just the final result. Re-do anything you got wrong the same day.What types of questions are covered for Compound Interest (Without Using Formula)?
A full mix — multiple-choice questions, assertion–reason questions, very short answer questions, short answer questions, long answer questions, case-based questions — so every format in the ICSE paper is covered.
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