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

Ragu invested Rs.72000 in two different parts one at 20% SI and another one at 20% CI (Compounded annually). What is the difference between the amount invested in SI and CI, if he received total interest at the end of two years is Rs.30480?

  1. 10000

  2. 15000

  3. 12000

  4. 8000

  5. 16000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let x be the amount at 20% SI and (72000 - x) be at 20% CI. SI = x * 0.2 * 2 = 0.4x. CI = (72000 - x) * ((1.2)^2 - 1) = (72000 - x) * 0.44. Total interest = 0.4x + 0.44(72000 - x) = 30480. Solving gives 0.04x = 31680 - 30480 = 1200, x = 30000. The other part is 42000. The difference is 12000.

Multiple choice

Aditya and Bhushan invested 10000 each in scheme A and scheme B respectively for 3 years. Scheme A offers Simple interest @ 12% per annum and scheme B offers compound interest @ 10%. After 3 years, who will have larger amount and by how much?

  1. Aditya, 280

  2. Bhushan, 280

  3. Adiya, 290

  4. Bhushan, 290

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

Aditya's simple interest is 10000 × 12% × 3 = 3600, so his amount is 13600. Bhushan's compound amount is 10000 × 1.1^3 = 13310, so Aditya has 290 more.

Multiple choice

Sanjana invested Rs. 15000 in SI at the rate of 2x% per annum for two years and the same amount is invested in CI at the same rate of interest if she received Rs.150 more interest than S.I, then find the rate of interest per annum?

  1. 10 %

  2. 14 %

  3. 12 %

  4. 16 %

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

Simple Interest (SI) = P * (2x/100) * 2 = 0.04Px. Compound Interest (CI) = P * (1 + 2x/100)^2 - P = P * (4x/100 + 4x^2/10000). The difference is CI - SI = P * (4x^2/10000) = 150. With P = 15000, 15000 * 4x^2 / 10000 = 150, so 6x^2 = 150, x^2 = 25, x = 5. The rate is 2x = 10%.

Multiple choice

Mohan invests certain amount of money for SI at 10% interest rate for one year and same amount for compound interest at 5% interest rate compounded annually for two years. If the sum of total interest is Rs. 16,200, then the amount invested by Mohan is

  1. Rs. 50,000

  2. Rs. 60,000

  3. Rs. 70,000

  4. Rs. 80,000

  5. Rs. 90,000
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

SI = P * 0.10 * 1 = 0.1P. CI = P * (1.05^2 - 1) = P * (1.1025 - 1) = 0.1025P. Total = 0.1P + 0.1025P = 0.2025P. 16200 = 0.2025P. P = 16200 / 0.2025 = 80000.

Multiple choice

Yoshua wanted to make an investment in the banking sector, so he invested a certain sum of money at d% interest per annum for 30 years. At the end of the period, he would get thrice the amount he invested. At what percentage of interest did he invest the money?

  1. 3.98%

  2. 4.33%

  3. 5.58%

  4. 6.67%

  5. 7.12%
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Simple interest I = P * r * t / 100. Here, the final amount is 3P, so interest I = 2P. 2P = P * r * 30 / 100. 2 = 0.3r. r = 2 / 0.3 = 6.666...% which rounds to 6.67%.

Multiple choice

Levi earned a certain amount of money from his business of handloom products. He thought he should invest this money to earn some interest, and his friend suggested him to invest this money at different rates of interests. Levi, then, invested 50% of the sum at the rate of 10% per annum. He invested 50% of the remaining at 16% per annum and the rest at 20% per annum. What would be the rate of interest annually, if the interest is calculated on the whole sum?

  1. 11%

  2. 12%

  3. 14%

  4. 15%

  5. 16%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let the total sum be 100. 50 is invested at 10% (interest 5). 25 is invested at 16% (interest 4). 25 is invested at 20% (interest 5). Total interest = 5 + 4 + 5 = 14. The annual rate is 14/100 = 14%.

Multiple choice

Suresh invested Rs.80000 in two different parts one at the rate of 20% CI per annum and another one at the rate of 15% SI per annum. If he interchanges the rate of interest he got Rs.2875 less at the end of two years, and then find the difference of the two sums

  1. Rs.20000

  2. Rs.24000

  3. Rs.12560

  4. Rs.14500

  5. Rs.17500
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let sums be x and y. x+y = 80000. Case 1: x at 20% CI, y at 15% SI. Case 2: y at 20% CI, x at 15% SI. The difference in interest is 2875. Solving the algebraic difference between the two interest expressions leads to the difference in principal.

Multiple choice

Mukesh invested Rs.30000 in two different parts one at 15% SI and another one at 20% CI. At the end of two year he received total interest Rs.10750 then find the amount invested in SI?

  1. Rs.12500

  2. Rs.15500

  3. Rs.21500

  4. Rs.17500

  5. Rs.18500
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let x be the amount at 15% SI and (30000-x) at 20% CI. SI = 0.3x. CI = (30000-x) * ((1.2)^2 - 1) = (30000-x) * 0.44 = 13200 - 0.44x. Total interest = 0.3x + 13200 - 0.44x = 10750. 0.14x = 2450. x = 17500.

Multiple choice

Ram gets 125% return on his investment after two years by investing in scheme A offering interest compounded annually. What will be the percent return received by him, if he invests in another scheme offering half rate of interest as that of scheme A compounded half yearly at the end of 2 years?

  1. 60.18%

  2. 55.14%

  3. 51.25%

  4. 48.75%

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

Scheme A: (1+r/100)^2 = 2.25 => 1+r/100 = 1.5 => r = 50%. Scheme B: Rate = 25%, compounded half-yearly for 2 years (4 periods). Amount = P * (1 + 12.5/100)^4 = P * (1.125)^4 = P * 1.6018. Return = 60.18%.