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

Simple interest on a certain sum for 3 years at 4% p.a. is Rs. 303.60. If the amount was kept at compound interest compounded annually, the difference between compound interest and simple interest would be

  1. Rs. 12.31

  2. Rs. 12.91

  3. Rs. 13.91

  4. Rs. 14.11
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Simple Interest = P*R*T/100 -> 303.60 = P*4*3/100 -> P = 2530. Compound Interest for 3 years at 4% = 2530 * ((1.04)^3 - 1) = 2530 * 0.124864 = 315.90592. Difference = 315.91 - 303.60 = 12.31.

Multiple choice

The compound interest on a certain sum of money at 5% per annum for 2 years is Rs. 230.20. The compound interest on the same sum of money for the same time period at 4% per annum will be

  1. Rs. 136.7

  2. Rs. 156.34

  3. Rs. 183.26

  4. Rs. 145.56

  5. Rs. 193.50
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CI = P * ((1+r/100)^n - 1). For 5%, 230.20 = P * ((1.05)^2 - 1) = P * 0.1025. P = 230.20 / 0.1025 = 2245.85. CI at 4% = 2245.85 * ((1.04)^2 - 1) = 2245.85 * 0.0816 = 183.26.

Multiple choice

A person invests the same amount of money at 10% per annum at simple interest and compound interest separately. After the completion of 3 years, he receives his payment and finds that there is a difference of Rs. 620 between the amounts. What is the amount of money he invested separately?

  1. Rs. 12000

  2. Rs. 18000

  3. Rs. 20000

  4. Rs. 25000

  5. Rs. 30000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

CI - SI for 3 years = P * (r/100)^2 * (3 + r/100). 620 = P * (0.1)^2 * (3.1) = P * 0.01 * 3.1 = P * 0.031. P = 620 / 0.031 = 20000.

Multiple choice

The simple interest on a certain amount will be 3/4 of the principal after a certain number of years. If the interest is Rs. 385.50 at the end of the second year, find the rate of interest per annum.

  1. 15%

  2. 14%

  3. 13%

  4. Data insufficient

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

Simple interest SI = P * R * T / 100. We are given SI = 3/4 P. So 3/4 P = P * R * T / 100. We know SI = 385.50 at T=2. This means 3/4 P = 385.50, so P = 514. But we don't have enough info to separate R and T definitively without assuming T=2 is the time for the 3/4 interest.

Multiple choice

The difference between simple interest and compound interest on a certain sum of money for four years at 10% per annum is $320.50. Find the sum.
  1. $5000
  2. $5500
  3. $6000
  4. $6500
  5. $7000
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For 4 years at 10% interest, the difference between compound interest (CI) and simple interest (SI) is given by P * ((1+r/100)^n - 1 - (n*r/100)). For n=4 and r=10%, the CI factor is 1.1^4 = 1.4641 and the SI factor is 1 + 0.4 = 1.4. The difference is 0.0641. Setting P * 0.0641 = 320.50 gives P = 320.50 / 0.0641 = 5000.

Multiple choice

Mr. Phanse invests an amount of Rs. 24200 at the rate of 4% p.a. for 6 years to obtain a simple interest. Later, he invests the principal amount as well as the amount obtained as simple interest for another 4 years at the same rate of interest. What amount of simple interest will he obtain at the end of the last 4 years?

  1. Rs. 4800

  2. Rs. 4800.32

  3. Rs. 4801.28

  4. Rs. 4700

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

Interest for 6 years = 24200 * 0.04 * 6 = 5808. New principal = 24200 + 5808 = 30008. Interest for next 4 years = 30008 * 0.04 * 4 = 4801.28.