Quantitative Aptitude

Simple and Compound Interest

3,394 Questions
All Simple interest and its inverse forms 768 Compound interest with annual compounding 742 Simple-interest growth and split sums 626 Difference between compound and simple interest 479 Half-yearly and quarterly compounding 252 Changing rates and fractional years 201 Installments (CI based) 190 Ratio of principal to interest 118 Population growth and depreciation 16

Simple and Compound Interest Questions

Multiple choice

What is the rate of interest if simple interest earned on a certain sum in three years is Rs 7200 and compound interest earned in 2 years at the same rate is Rs 5160 ?

  1. 12.5%

  2. 12%

  3. 15%

  4. 18%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let principal be P and rate be R%. Simple interest for 3 years: 3PR/100 = 7200, so PR = 240000. Compound interest for 2 years: P[(1 + R/100)² - 1] = 5160. Substituting P = 240000/R: (240000/R)[(1 + R/100)² - 1] = 5160. Testing R = 15%: (240000/15)[1.3225 - 1] = 16000 × 0.3225 = 5160. This matches exactly.

Multiple choice

If compound interest received on a certain amount in the 3rd year is Rs. 7056, what will be the compound interest (in Rs) for the 4th year on the same amount if rate of interest is 12% ?

  1. 7784.24

  2. 7854.5

  3. 7896.24

  4. 7902.72
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let principal be P. CI in 3rd year = P(1.12)³ - P(1.12)² = P × 1.12² × 0.12 = 7056. So P × 1.2544 × 0.12 = 7056, giving P = 7056/0.150528 = 49000 (approx). CI in 4th year = P(1.12)⁴ - P(1.12)³ = P × 1.12³ × 0.12 = 49000 × 1.404928 × 0.12 = 7902.72.

Multiple choice

Pawan invested a total of Rs.35000 in two different schemes A and B. The scheme A which offers interest at a rate of 5% per annum and scheme B offers interest at a rate of 12%. If the total interest earned by Pawan after 1 year is Rs.3500 then find the sum invested in scheme B.

  1. 27000

  2. 25000

  3. 28000

  4. 22000

  5. 26000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let amount in scheme B be x, so scheme A is 35000-x. Interest: 0.12x + 0.05(35000-x) = 3500. Solving: 0.12x + 1750 - 0.05x = 3500, so 0.07x = 1750, giving x = 25000. Pawan invested Rs. 25000 in scheme B at 12% to earn the desired total interest.

Multiple choice

A builder borrows 2550 to be paid back with compound interest at the rate of 4% per annum by the end of 2 years in two equal yearly instalments. How much will each instalment be?

  1. 1352

  2. 1377

  3. 1275

  4. 1283

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For compound interest with equal yearly instalments, let each instalment be x. After 1 year, amount is 2550(1.04). Pay x, balance is 2550(1.04) - x. After 2nd year, this becomes (2550(1.04) - x)(1.04). This equals x. Solving: 2550(1.04²) - x(1.04) = x, so x = 2550(1.0816)/2.04 ≈ 1352. Each instalment is approximately Rs. 1352.

Multiple choice

Sum of money is invested in Scheme A, 12% per annum, After 2 years amount is received, that amount invested in scheme B at 10% per annum for compound interest. If the interest received at the end of 2 years is 5208. Find the sum? राशि का निवेश योजना A में 12% प्रतिवर्ष किया जाता है, 2 वर्ष की राशि प्राप्त होने के बाद, योजना B में 10% प्रति वर्ष चक्रवृद्धि ब्याज के लिए निवेश की गई । यदि 2 वर्ष के अंत में प्राप्त ब्याज 5208 है। राशि ज्ञात कीजिए?

  1. 20000

  2. 16000

  3. 15680

  4. 24580

  5. 22650
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let sum be P. After 2 years at 12% SI: amount = P(1 + 0.12×2) = 1.24P. This is invested at 10% CI for 2 years: maturity = 1.24P(1.1)² = 1.24P × 1.21 = 1.5004P. Interest = 1.5004P - 1.24P = 0.2604P = 5208. So P = 5208/0.2604 = 20000. The key is tracking principal through both investment stages.

Multiple choice

Simple interest on a certain sum is one-fourth of the sum and the interest rate percentage per annum is 4 times the number of years. If the rate of interest increases by 2%, then what will be the simple interest (in ₹) on ₹5,000 for 3 years?

  1. 2000

  2. 1800

  3. 300

  4. 1500
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the sum be P and time be t years. SI = P/4 = (P × r × t)/100 gives rt = 25. Given r = 4t, we get 4t² = 25, so t = 2.5 years and r = 10%. New rate = 12%, so SI on ₹5000 for 3 years = (5000 × 12 × 3)/100 = ₹1800.

Multiple choice

what will be the compound interest earned on a sum of Rs. 160000 for 3 years when the interest rate is 20% which is calculated every 9 months ?

  1. 119880

  2. 119650

  3. 119885

  4. 119841
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

When interest is compounded every 9 months, the annual rate of 20% converts to 15% per period (20% × 9/12). In 3 years, there are 4 compounding periods. Amount = 160000(1.15)^4 ≈ 279841, so CI ≈ 119841. If 20% per 9-month period were used, CI would be ~171776, which matches no option.

Multiple choice

A certain sum of money at certain rate of compound interest amounts to Rs 1,200 in 7 years and Rs 1,344 in 8 years. Find the rate of interest? एक निश्चित धनराशि, निश्चित चक्रवृद्धि ब्याज की दर से 7 वर्षों में 1200 रुपये तथा 8 वर्षों में 1344रु हो जाती है। ब्याज की दर ज्ञात कीजिये।

  1. 14%

  2. 15%

  3. 20%

  4. 10%

  5. None of these. इनमे से कोई नहीं
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

For compound interest, amount increases by (1 + r) each year. A₈/A₇ = 1344/1200 = 1.12. Therefore 1 + r = 1.12, so r = 0.12 = 12%. Rate is 12%, not in options A-D.

Multiple choice

David invested certain amount in three different schemes A, B and C with the rate of interest 10% p.a., 12% p.a. and 15% p.a. respectively. If the the total interest accrued in one year was Rs 3200 and the amount invested in Scheme C was 150 % of the amount invested in Scheme A and 240% of the amount invested in Scheme B, what was the amount invested in Scheme B?

  1. 5000

  2. 8000

  3. 6500

  4. cannot be determined

  5. None of these
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let amounts in A, B, C be x, y, z respectively. Given z = 150% of x = 1.5x and z = 240% of y = 2.4y. From interest equation: 0.1x + 0.12y + 0.15z = 3200. Substituting x = 2z/3 and y = 5z/12 gives 0.1(2z/3) + 0.12(5z/12) + 0.15z = 3200. Solving yields z = 12000, so y = 5/12 × 12000 = 5000. Option A is correct.

Multiple choice

Pankaj invested a certain amount in three different schemes A, B, and C with the rate of interest 8% p.a., 10% p.a. and 12% p.a. respectively. If the total interest accrued in one year was Rs. 6560 and the amount invested in Scheme C was 140% of the amount invested in Scheme A and 175% of the amount invested in Scheme B, what was the amount invested in Scheme B?

  1. 12000

  2. 14000

  3. 16000

  4. 12500

  5. None of these
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let A=100x, then C=140% of A=140x. Also C=175% of B, so 140x=1.75B, B=80x. Interest: 8% of A + 10% of B + 12% of C = 6560. 8x + 8x + 16.8x = 6560. 32.8x=6560, x=200. B=80x=16000. Check: A=20000 (8%=1600), B=16000 (10%=1600), C=28000 (12%=3360). Total interest = 1600+1600+3360=6560. ✓