Simple Interest & Compound Interest Practice

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Practice Simple Interest & Compound Interest the Exam Way

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SI Formula
1. What is the simple interest on Rs 14,000 at 15% for 3 years?
- A. Rs 5,800
- B. Rs 6,000
- C. Rs 6,300 (Correct)
- D. Rs 6,500
Explanation: $SI=\frac{PRT}{100}=\frac{14000\times15\times3}{100}=6300$.
Principal from SI
2. A sum earns Rs 1,920 as SI in 4 years at 8%. Find the principal.
- A. Rs 5,000
- B. Rs 6,000 (Correct)
- C. Rs 7,000
- D. Rs 8,000
Explanation: $P=\frac{SI\times100}{RT}=\frac{1920\times100}{8\times4}=6000$.
Rate from SI
3. At what rate will Rs 8,000 earn Rs 2,400 in 5 years under SI?
- A. 4%
- B. 5%
- C. 6% (Correct)
- D. 7%
Explanation: $R=\frac{SI\times100}{PT}=\frac{2400\times100}{8000\times5}=6\%$.
Time from Amount
4. In how many years will Rs 12,500 amount to Rs 16,250 at 10% SI?
- A. 2 years
- B. 3 years (Correct)
- C. 4 years
- D. 5 years
Explanation: Interest = 16250 - 12500 = 3750. $T=\frac{3750\times100}{12500\times10}=3$ years.
Doubling in SI
5. A sum doubles under SI in 12 years. It will become 1.5 times in:
- A. 4 years
- B. 5 years
- C. 6 years (Correct)
- D. 8 years
Explanation: If a sum doubles, interest = P in 12 years. For 1.5 times, interest needed = 0.5P, so the time is half of 12 years.
Months to Years
6. A loan of Rs 30,000 is taken for 9 months at 16% SI. Find the interest.
- A. Rs 3,200
- B. Rs 3,400
- C. Rs 3,600 (Correct)
- D. Rs 4,000
Explanation: Time = 9/12 = 0.75 year. $SI=30000\times16\times0.75/100=3600$.
Principal from Amount
7. A sum becomes Rs 28,600 in 2 years at 5% SI. Find the principal.
- A. Rs 24,000
- B. Rs 25,000
- C. Rs 26,000 (Correct)
- D. Rs 27,000
Explanation: $A=P(1+RT/100)=1.1P$. So $P=28600/1.1=26000$.
Simple Interest
8. The SI on Rs 18,000 at 7.5% for 2 years is:
- A. Rs 2,600
- B. Rs 2,700 (Correct)
- C. Rs 2,800
- D. Rs 2,900
Explanation: $SI=\frac{18000\times7.5\times2}{100}=2700$.
Tripling in SI
9. A sum triples in 16 years at SI. What is the rate?
- A. 10%
- B. 11.5%
- C. 12.5% (Correct)
- D. 15%
Explanation: Tripling means interest = 2P. So $RT=200$. With $T=16$, $R=12.5\%$.
Amount under SI
10. The amount on Rs 10,000 at 8% SI for 2 years is:
- A. Rs 11,400
- B. Rs 11,500
- C. Rs 11,600 (Correct)
- D. Rs 11,800
Explanation: Interest = 10000 x 8 x 2 / 100 = 1600. Amount = 10000 + 1600 = 11600.
Annual CI
11. Find the amount on Rs 9,000 for 2 years at 10% compounded annually.
- A. Rs 10,780
- B. Rs 10,890 (Correct)
- C. Rs 10,920
- D. Rs 10,980
Explanation: $A=9000(1.1)^2=10890$.
Annual CI
12. The CI on Rs 12,000 for 3 years at 5% annually is:
- A. Rs 1,791.50
- B. Rs 1,891.50 (Correct)
- C. Rs 1,990.50
- D. Rs 2,025
Explanation: $A=12000(1.05)^3=13891.50$. So $CI=1891.50$.
Principal from CI
13. A sum becomes Rs 13,225 in 2 years at 15% annually. Find the principal.
- A. Rs 9,500
- B. Rs 10,000 (Correct)
- C. Rs 10,200
- D. Rs 10,500
Explanation: $P=13225/(1.15)^2=10000$.
Rate from CI
14. At what rate will Rs 25,000 amount to Rs 30,250 in 2 years at annual CI?
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1+r)^2=30250/25000=1.21$. So $r=10\%$.
Time from CI
15. How many years will Rs 16,000 become Rs 19,360 at 10% annual CI?
- A. 1
- B. 2 (Correct)
- C. 3
- D. 4
Explanation: $16000(1.1)^2=19360$, so the time is 2 years.
One-Year CI
16. CI on Rs 20,000 at 12% for 1 year is:
- A. Rs 2,200
- B. Rs 2,300
- C. Rs 2,400 (Correct)
- D. Rs 2,500
Explanation: For one year, CI = SI. $20000\times12/100=2400$.
Annual CI
17. The amount after 3 years on Rs 5,000 at 20% annual CI is:
- A. Rs 8,540
- B. Rs 8,620
- C. Rs 8,640 (Correct)
- D. Rs 8,700
Explanation: $A=5000(1.2)^3=8640$.
Principal from CI
18. A sum earns Rs 1,680 as CI in 2 years at 20%. Find the principal.
- A. Rs 3,500
- B. Rs 3,800
- C. Rs 4,000 (Correct)
- D. Rs 4,200
Explanation: For 2 years at 20%, CI fraction = $(1.2)^2-1=0.44$. So $0.44P=1680$, giving $P=4000$.
Annual CI
19. The amount on Rs 30,000 for 2 years at 6% CI is:
- A. Rs 33,708 (Correct)
- B. Rs 33,816
- C. Rs 33,908
- D. Rs 34,020
Explanation: $A=30000(1.06)^2=33708$.
Annual CI
20. A principal becomes Rs 46,656 in 3 years at 8% CI. Find the nearest principal.
- A. Rs 37,000
- B. Rs 37,050 (Correct)
- C. Rs 37,100
- D. Rs 37,150
Explanation: $P=46656/(1.08)^3\approx37050.75$. The nearest option is Rs 37,050.
Half-Yearly CI
21. Find the amount on Rs 16,000 at 10% p.a. compounded half-yearly for 1 year.
- A. Rs 17,600
- B. Rs 17,640 (Correct)
- C. Rs 17,680
- D. Rs 17,700
Explanation: Half-yearly rate = 5% and periods = 2. $A=16000(1.05)^2=17640$.
Half-Yearly CI
22. CI on Rs 25,000 for 6 months at 8% p.a. compounded half-yearly is:
- A. Rs 800
- B. Rs 1,000 (Correct)
- C. Rs 1,200
- D. Rs 1,400
Explanation: One half-year period at 4% gives CI = 25000 x 4 / 100 = 1000.
CI-SI Difference
23. The difference between CI and SI on Rs 18,000 for 2 years at 10% is:
- A. Rs 160
- B. Rs 180 (Correct)
- C. Rs 200
- D. Rs 220
Explanation: For 2 years, difference = $P(R/100)^2$. = 18000 x 0.01 = 180.
CI-SI Difference
24. On what sum will the difference between CI and SI for 2 years at 5% be Rs 25?
- A. Rs 8,000
- B. Rs 9,000
- C. Rs 10,000 (Correct)
- D. Rs 12,000
Explanation: At 5%, difference for 2 years = $P\times25/10000=P/400$. So $P/400=25$ gives $P=10000$.
Mixed Rates
25. A sum is invested at 10%, 10%, and 20% in three successive years under CI. If principal is Rs 5,000, the amount is:
- A. Rs 7,200
- B. Rs 7,260 (Correct)
- C. Rs 7,300
- D. Rs 7,350
Explanation: $A=5000\times1.1\times1.1\times1.2=7260$.
Effective Rate
26. What is the effective annual rate of 12% p.a. compounded half-yearly?
- A. 12.00%
- B. 12.25%
- C. 12.36% (Correct)
- D. 12.50%
Explanation: Effective rate = $(1.06)^2 - 1 = 0.1236 = 12.36\%$.
Quarterly CI
27. The amount on Rs 40,000 for 9 months at 12% p.a. compounded quarterly is:
- A. Rs 43,272
- B. Rs 43,708 (Correct)
- C. Rs 43,927
- D. Rs 44,000
Explanation: Quarterly rate = 3% and periods = 3. $A=40000(1.03)^3=43708.36$, approximately Rs 43,708.
SI from CI Data
28. A sum at 8% compounded annually becomes Rs 11,664 in 2 years. Find SI on the same principal, same rate, same time.
- A. Rs 1,520
- B. Rs 1,600 (Correct)
- C. Rs 1,680
- D. Rs 1,760
Explanation: First find the principal: $P=11664/(1.08)^2=10000$. Then SI = $10000\times8\times2/100 = 1600$.
Annual vs Half-Yearly
29. The difference between half-yearly and annual amount on Rs 20,000 for 1 year at 10% is:
- A. Rs 25
- B. Rs 50 (Correct)
- C. Rs 75
- D. Rs 100
Explanation: Half-yearly amount = 20000(1.05)^2 = 22050. Annual amount = 22000. Difference = 50.
Powers in CI
30. At 10% annual CI, in how many years will a sum become 1.331 times?
- A. 1
- B. 2
- C. 3 (Correct)
- D. 4
Explanation: Since $1.1^3=1.331$, the time is 3 years.
Population Growth
31. The population of a village is 80,000 and grows by 5% every year. Find the population after 2 years.
- A. 88,000
- B. 88,200 (Correct)
- C. 88,400
- D. 88,600
Explanation: Population after 2 years = $80000(1.05)^2=88200$.
Depreciation
32. A machine depreciates by 20% every year. If current value is Rs 25,600 after 2 years, original price was:
- A. Rs 36,000
- B. Rs 38,000
- C. Rs 40,000 (Correct)
- D. Rs 42,000
Explanation: $P(0.8)^2=25600$. So $P=25600/0.64=40000$.
Reverse Growth
33. A tree grows by 10% every year. If height is 121 cm after 2 years, present height is:
- A. 95 cm
- B. 100 cm (Correct)
- C. 105 cm
- D. 110 cm
Explanation: Present height = $121/(1.1)^2 = 100$ cm.
Debt Amount
34. A debt of Rs 12,000 at 10% annual CI is cleared after 2 years. What amount is paid?
- A. Rs 14,400
- B. Rs 14,520 (Correct)
- C. Rs 14,600
- D. Rs 14,700
Explanation: Amount = $12000(1.1)^2=14520$.
Simple Interest Application
35. If Rs 5,000 is borrowed at 12% SI and repaid after 8 months, interest is:
- A. Rs 300
- B. Rs 360
- C. Rs 400 (Correct)
- D. Rs 480
Explanation: Time = 8/12 year. $SI=5000\times12\times(8/12)/100=400$.
Present Worth
36. Present worth of Rs 12,100 due after 2 years at 10% CI is:
- A. Rs 9,500
- B. Rs 10,000 (Correct)
- C. Rs 10,500
- D. Rs 11,000
Explanation: Present worth = $12100/(1.1)^2 = 10000$.
Future Value
37. A student deposits Rs 25,000 at 8% annual CI. What will be the amount after 3 years?
- A. Rs 31,492
- B. Rs 31,493 (Correct)
- C. Rs 31,496
- D. Rs 31,500
Explanation: $A=25000(1.08)^3=31492.8$, approximately Rs 31,493.
Depreciation Rate
38. An article depreciates from Rs 50,000 to Rs 40,500 in 2 years. The annual depreciation rate is:
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1-r)^2=40500/50000=0.81$. So $1-r=0.9$ and $r=10\%$.
Multiplier Logic
39. At SI, a sum becomes four times in 15 years. In how many years will it become seven times?
- A. 25
- B. 30 (Correct)
- C. 35
- D. 40
Explanation: Four times means interest = 3P in 15 years. Seven times means interest = 6P, which needs double the time, i.e. 30 years.
Rate from Growth
40. If Rs 10,000 under CI grows to Rs 12,100 in 2 years, what is the annual rate?
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1+r)^2=12100/10000=1.21$. So $r=10\%$.
Simple Interest
41. A sum gives Rs 2,160 simple interest in 3 years at 12% p.a. Find the principal.
- A. Rs 5,000
- B. Rs 5,500
- C. Rs 6,000 (Correct)
- D. Rs 6,500
Explanation: $SI=PRT/100$. $2160=P\times12\times3/100$, so $P=6000$.
CI vs SI
42. The difference between compound interest and simple interest on a sum for 2 years at 10% is Rs 80. Find the principal.
- A. Rs 6,000
- B. Rs 7,000
- C. Rs 8,000 (Correct)
- D. Rs 9,000
Explanation: For 2 years, CI - SI $=P\times(r/100)^2$. $80=P\times(10/100)^2=P/100$, so $P=8000$.
Half-Yearly CI
43. Find the amount on Rs 16,000 for 1 year at 10% p.a. compounded half-yearly.
- A. Rs 17,600
- B. Rs 17,640 (Correct)
- C. Rs 17,680
- D. Rs 17,700
Explanation: Half-yearly rate = 5%, periods = 2. Amount $=16000(1.05)^2=17640$.
Depreciation
44. A laptop worth Rs 72,000 depreciates by 20% in the first year and 10% in the second year. Its value after 2 years is:
- A. Rs 50,840
- B. Rs 51,840 (Correct)
- C. Rs 52,840
- D. Rs 53,840
Explanation: Value factor $=0.8\times0.9=0.72$. Value $=72000\times0.72=51840$.
Rate from Amount
45. A sum becomes Rs 13,310 in 3 years at annual compound interest. If the principal is Rs 10,000, the annual rate is:
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $13310/10000=1.331$. Since $1.1^3=1.331$, the annual rate is 10%.

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Practice Simple Interest & Compound Interest the Exam Way

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SI Formula
1. What is the simple interest on Rs 14,000 at 15% for 3 years?
- A. Rs 5,800
- B. Rs 6,000
- C. Rs 6,300 (Correct)
- D. Rs 6,500
Explanation: $SI=\frac{PRT}{100}=\frac{14000\times15\times3}{100}=6300$.
Principal from SI
2. A sum earns Rs 1,920 as SI in 4 years at 8%. Find the principal.
- A. Rs 5,000
- B. Rs 6,000 (Correct)
- C. Rs 7,000
- D. Rs 8,000
Explanation: $P=\frac{SI\times100}{RT}=\frac{1920\times100}{8\times4}=6000$.
Rate from SI
3. At what rate will Rs 8,000 earn Rs 2,400 in 5 years under SI?
- A. 4%
- B. 5%
- C. 6% (Correct)
- D. 7%
Explanation: $R=\frac{SI\times100}{PT}=\frac{2400\times100}{8000\times5}=6\%$.
Time from Amount
4. In how many years will Rs 12,500 amount to Rs 16,250 at 10% SI?
- A. 2 years
- B. 3 years (Correct)
- C. 4 years
- D. 5 years
Explanation: Interest = 16250 - 12500 = 3750. $T=\frac{3750\times100}{12500\times10}=3$ years.
Doubling in SI
5. A sum doubles under SI in 12 years. It will become 1.5 times in:
- A. 4 years
- B. 5 years
- C. 6 years (Correct)
- D. 8 years
Explanation: If a sum doubles, interest = P in 12 years. For 1.5 times, interest needed = 0.5P, so the time is half of 12 years.
Months to Years
6. A loan of Rs 30,000 is taken for 9 months at 16% SI. Find the interest.
- A. Rs 3,200
- B. Rs 3,400
- C. Rs 3,600 (Correct)
- D. Rs 4,000
Explanation: Time = 9/12 = 0.75 year. $SI=30000\times16\times0.75/100=3600$.
Principal from Amount
7. A sum becomes Rs 28,600 in 2 years at 5% SI. Find the principal.
- A. Rs 24,000
- B. Rs 25,000
- C. Rs 26,000 (Correct)
- D. Rs 27,000
Explanation: $A=P(1+RT/100)=1.1P$. So $P=28600/1.1=26000$.
Simple Interest
8. The SI on Rs 18,000 at 7.5% for 2 years is:
- A. Rs 2,600
- B. Rs 2,700 (Correct)
- C. Rs 2,800
- D. Rs 2,900
Explanation: $SI=\frac{18000\times7.5\times2}{100}=2700$.
Tripling in SI
9. A sum triples in 16 years at SI. What is the rate?
- A. 10%
- B. 11.5%
- C. 12.5% (Correct)
- D. 15%
Explanation: Tripling means interest = 2P. So $RT=200$. With $T=16$, $R=12.5\%$.
Amount under SI
10. The amount on Rs 10,000 at 8% SI for 2 years is:
- A. Rs 11,400
- B. Rs 11,500
- C. Rs 11,600 (Correct)
- D. Rs 11,800
Explanation: Interest = 10000 x 8 x 2 / 100 = 1600. Amount = 10000 + 1600 = 11600.
Annual CI
11. Find the amount on Rs 9,000 for 2 years at 10% compounded annually.
- A. Rs 10,780
- B. Rs 10,890 (Correct)
- C. Rs 10,920
- D. Rs 10,980
Explanation: $A=9000(1.1)^2=10890$.
Annual CI
12. The CI on Rs 12,000 for 3 years at 5% annually is:
- A. Rs 1,791.50
- B. Rs 1,891.50 (Correct)
- C. Rs 1,990.50
- D. Rs 2,025
Explanation: $A=12000(1.05)^3=13891.50$. So $CI=1891.50$.
Principal from CI
13. A sum becomes Rs 13,225 in 2 years at 15% annually. Find the principal.
- A. Rs 9,500
- B. Rs 10,000 (Correct)
- C. Rs 10,200
- D. Rs 10,500
Explanation: $P=13225/(1.15)^2=10000$.
Rate from CI
14. At what rate will Rs 25,000 amount to Rs 30,250 in 2 years at annual CI?
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1+r)^2=30250/25000=1.21$. So $r=10\%$.
Time from CI
15. How many years will Rs 16,000 become Rs 19,360 at 10% annual CI?
- A. 1
- B. 2 (Correct)
- C. 3
- D. 4
Explanation: $16000(1.1)^2=19360$, so the time is 2 years.
One-Year CI
16. CI on Rs 20,000 at 12% for 1 year is:
- A. Rs 2,200
- B. Rs 2,300
- C. Rs 2,400 (Correct)
- D. Rs 2,500
Explanation: For one year, CI = SI. $20000\times12/100=2400$.
Annual CI
17. The amount after 3 years on Rs 5,000 at 20% annual CI is:
- A. Rs 8,540
- B. Rs 8,620
- C. Rs 8,640 (Correct)
- D. Rs 8,700
Explanation: $A=5000(1.2)^3=8640$.
Principal from CI
18. A sum earns Rs 1,680 as CI in 2 years at 20%. Find the principal.
- A. Rs 3,500
- B. Rs 3,800
- C. Rs 4,000 (Correct)
- D. Rs 4,200
Explanation: For 2 years at 20%, CI fraction = $(1.2)^2-1=0.44$. So $0.44P=1680$, giving $P=4000$.
Annual CI
19. The amount on Rs 30,000 for 2 years at 6% CI is:
- A. Rs 33,708 (Correct)
- B. Rs 33,816
- C. Rs 33,908
- D. Rs 34,020
Explanation: $A=30000(1.06)^2=33708$.
Annual CI
20. A principal becomes Rs 46,656 in 3 years at 8% CI. Find the nearest principal.
- A. Rs 37,000
- B. Rs 37,050 (Correct)
- C. Rs 37,100
- D. Rs 37,150
Explanation: $P=46656/(1.08)^3\approx37050.75$. The nearest option is Rs 37,050.
Half-Yearly CI
21. Find the amount on Rs 16,000 at 10% p.a. compounded half-yearly for 1 year.
- A. Rs 17,600
- B. Rs 17,640 (Correct)
- C. Rs 17,680
- D. Rs 17,700
Explanation: Half-yearly rate = 5% and periods = 2. $A=16000(1.05)^2=17640$.
Half-Yearly CI
22. CI on Rs 25,000 for 6 months at 8% p.a. compounded half-yearly is:
- A. Rs 800
- B. Rs 1,000 (Correct)
- C. Rs 1,200
- D. Rs 1,400
Explanation: One half-year period at 4% gives CI = 25000 x 4 / 100 = 1000.
CI-SI Difference
23. The difference between CI and SI on Rs 18,000 for 2 years at 10% is:
- A. Rs 160
- B. Rs 180 (Correct)
- C. Rs 200
- D. Rs 220
Explanation: For 2 years, difference = $P(R/100)^2$. = 18000 x 0.01 = 180.
CI-SI Difference
24. On what sum will the difference between CI and SI for 2 years at 5% be Rs 25?
- A. Rs 8,000
- B. Rs 9,000
- C. Rs 10,000 (Correct)
- D. Rs 12,000
Explanation: At 5%, difference for 2 years = $P\times25/10000=P/400$. So $P/400=25$ gives $P=10000$.
Mixed Rates
25. A sum is invested at 10%, 10%, and 20% in three successive years under CI. If principal is Rs 5,000, the amount is:
- A. Rs 7,200
- B. Rs 7,260 (Correct)
- C. Rs 7,300
- D. Rs 7,350
Explanation: $A=5000\times1.1\times1.1\times1.2=7260$.
Effective Rate
26. What is the effective annual rate of 12% p.a. compounded half-yearly?
- A. 12.00%
- B. 12.25%
- C. 12.36% (Correct)
- D. 12.50%
Explanation: Effective rate = $(1.06)^2 - 1 = 0.1236 = 12.36\%$.
Quarterly CI
27. The amount on Rs 40,000 for 9 months at 12% p.a. compounded quarterly is:
- A. Rs 43,272
- B. Rs 43,708 (Correct)
- C. Rs 43,927
- D. Rs 44,000
Explanation: Quarterly rate = 3% and periods = 3. $A=40000(1.03)^3=43708.36$, approximately Rs 43,708.
SI from CI Data
28. A sum at 8% compounded annually becomes Rs 11,664 in 2 years. Find SI on the same principal, same rate, same time.
- A. Rs 1,520
- B. Rs 1,600 (Correct)
- C. Rs 1,680
- D. Rs 1,760
Explanation: First find the principal: $P=11664/(1.08)^2=10000$. Then SI = $10000\times8\times2/100 = 1600$.
Annual vs Half-Yearly
29. The difference between half-yearly and annual amount on Rs 20,000 for 1 year at 10% is:
- A. Rs 25
- B. Rs 50 (Correct)
- C. Rs 75
- D. Rs 100
Explanation: Half-yearly amount = 20000(1.05)^2 = 22050. Annual amount = 22000. Difference = 50.
Powers in CI
30. At 10% annual CI, in how many years will a sum become 1.331 times?
- A. 1
- B. 2
- C. 3 (Correct)
- D. 4
Explanation: Since $1.1^3=1.331$, the time is 3 years.
Population Growth
31. The population of a village is 80,000 and grows by 5% every year. Find the population after 2 years.
- A. 88,000
- B. 88,200 (Correct)
- C. 88,400
- D. 88,600
Explanation: Population after 2 years = $80000(1.05)^2=88200$.
Depreciation
32. A machine depreciates by 20% every year. If current value is Rs 25,600 after 2 years, original price was:
- A. Rs 36,000
- B. Rs 38,000
- C. Rs 40,000 (Correct)
- D. Rs 42,000
Explanation: $P(0.8)^2=25600$. So $P=25600/0.64=40000$.
Reverse Growth
33. A tree grows by 10% every year. If height is 121 cm after 2 years, present height is:
- A. 95 cm
- B. 100 cm (Correct)
- C. 105 cm
- D. 110 cm
Explanation: Present height = $121/(1.1)^2 = 100$ cm.
Debt Amount
34. A debt of Rs 12,000 at 10% annual CI is cleared after 2 years. What amount is paid?
- A. Rs 14,400
- B. Rs 14,520 (Correct)
- C. Rs 14,600
- D. Rs 14,700
Explanation: Amount = $12000(1.1)^2=14520$.
Simple Interest Application
35. If Rs 5,000 is borrowed at 12% SI and repaid after 8 months, interest is:
- A. Rs 300
- B. Rs 360
- C. Rs 400 (Correct)
- D. Rs 480
Explanation: Time = 8/12 year. $SI=5000\times12\times(8/12)/100=400$.
Present Worth
36. Present worth of Rs 12,100 due after 2 years at 10% CI is:
- A. Rs 9,500
- B. Rs 10,000 (Correct)
- C. Rs 10,500
- D. Rs 11,000
Explanation: Present worth = $12100/(1.1)^2 = 10000$.
Future Value
37. A student deposits Rs 25,000 at 8% annual CI. What will be the amount after 3 years?
- A. Rs 31,492
- B. Rs 31,493 (Correct)
- C. Rs 31,496
- D. Rs 31,500
Explanation: $A=25000(1.08)^3=31492.8$, approximately Rs 31,493.
Depreciation Rate
38. An article depreciates from Rs 50,000 to Rs 40,500 in 2 years. The annual depreciation rate is:
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1-r)^2=40500/50000=0.81$. So $1-r=0.9$ and $r=10\%$.
Multiplier Logic
39. At SI, a sum becomes four times in 15 years. In how many years will it become seven times?
- A. 25
- B. 30 (Correct)
- C. 35
- D. 40
Explanation: Four times means interest = 3P in 15 years. Seven times means interest = 6P, which needs double the time, i.e. 30 years.
Rate from Growth
40. If Rs 10,000 under CI grows to Rs 12,100 in 2 years, what is the annual rate?
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $(1+r)^2=12100/10000=1.21$. So $r=10\%$.
Simple Interest
41. A sum gives Rs 2,160 simple interest in 3 years at 12% p.a. Find the principal.
- A. Rs 5,000
- B. Rs 5,500
- C. Rs 6,000 (Correct)
- D. Rs 6,500
Explanation: $SI=PRT/100$. $2160=P\times12\times3/100$, so $P=6000$.
CI vs SI
42. The difference between compound interest and simple interest on a sum for 2 years at 10% is Rs 80. Find the principal.
- A. Rs 6,000
- B. Rs 7,000
- C. Rs 8,000 (Correct)
- D. Rs 9,000
Explanation: For 2 years, CI - SI $=P\times(r/100)^2$. $80=P\times(10/100)^2=P/100$, so $P=8000$.
Half-Yearly CI
43. Find the amount on Rs 16,000 for 1 year at 10% p.a. compounded half-yearly.
- A. Rs 17,600
- B. Rs 17,640 (Correct)
- C. Rs 17,680
- D. Rs 17,700
Explanation: Half-yearly rate = 5%, periods = 2. Amount $=16000(1.05)^2=17640$.
Depreciation
44. A laptop worth Rs 72,000 depreciates by 20% in the first year and 10% in the second year. Its value after 2 years is:
- A. Rs 50,840
- B. Rs 51,840 (Correct)
- C. Rs 52,840
- D. Rs 53,840
Explanation: Value factor $=0.8\times0.9=0.72$. Value $=72000\times0.72=51840$.
Rate from Amount
45. A sum becomes Rs 13,310 in 3 years at annual compound interest. If the principal is Rs 10,000, the annual rate is:
- A. 8%
- B. 9%
- C. 10% (Correct)
- D. 11%
Explanation: $13310/10000=1.331$. Since $1.1^3=1.331$, the annual rate is 10%.

Simple Interest & Compound Interest Practice

Practice Simple Interest & Compound Interest the Exam Way

Simple Interest Fundamentals

Compound Interest Core

Frequency & Comparison

Applications

40-question mixed challenge

Practice Simple Interest & Compound Interest the Exam Way

Simple Interest Fundamentals

Compound Interest Core

Frequency & Comparison

Applications

40-question mixed challenge