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

Total amount of simple interest earned by a person in 2 years is Rs. 4140. He invested Rs. 15,500 in two different schemes X and Y at 15% and 12% simple interest per annum. Find the amount invested by the person in scheme Y.

  1. Rs. 6210

  2. Rs. 7020

  3. Rs. 8500

  4. Rs. 9100

  5. Rs. 9350
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let x be the amount in scheme X and (15500-x) in scheme Y. Interest = (x * 0.15 * 2) + ((15500-x) * 0.12 * 2) = 4140. 0.3x + 3720 - 0.24x = 4140. 0.06x = 420. x = 7000. Amount in Y = 15500 - 7000 = 8500.

Multiple choice

Mrs. Rini Khan deposited Rs. X in a company at 17% per annum simple interest for 5 years and deposited an equal amount for fixed deposit in a bank 'A' for 4 years at 16% per annum simple interest. The interest from the company is Rs. 2,520 more than the interest from the bank. Mrs. Khan deposited Rs. (X + 8,000) in another bank 'B' at r% compound interest for 3 years. If after three years, Mrs. Khan received Rs. 26,620, find the compound interest on Rs. 25,000 at (r + 10)% for 2 years.

  1. Rs. 10,000

  2. Rs. 11,000

  3. Rs. 12,000

  4. Rs. 9,000

  5. Rs. 13,000
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

From the interest difference: (X * 0.17 * 5) - (X * 0.16 * 4) = 2520, leading to 0.85X - 0.64X = 2520, so 0.21X = 2520, X = 12000. For bank B: (12000 + 8000) * (1 + r/100)^3 = 26620, so (1 + r/100)^3 = 1.331, meaning 1 + r/100 = 1.1, r = 10%. The compound interest on 25000 at 20% for 2 years is 25000 * (1.2^2 - 1) = 25000 * 0.44 = 11000.

Multiple choice

A took two loans altogether for Rs. 1200 from B and C. B claimed 14% simple interest per annum, while C claimed 15% per annum. The total interest paid by A in one year was Rs. 172. Then, A borrowed

  1. Rs. 800 from C

  2. Rs. 625 from C

  3. Rs. 400 from B

  4. Rs. 800 from B
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let x be the amount borrowed from B and (1200 - x) be the amount from C. The interest equation is 0.14x + 0.15(1200 - x) = 172. Solving this gives 0.14x + 180 - 0.15x = 172, so 0.01x = 8, meaning x = 800.

Multiple choice

A person has left an amount of Rs. 1,20,000 to be divided between his two sons, aged 14 years and 12 years such that they get equal amounts when each attains 18 years of age. If the amount gets a simple interest of 5% per annum, the younger son's share at present is

  1. Rs. 48,800

  2. Rs. 57,600

  3. Rs. 62,400

  4. Rs. 84,400
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let younger son's share be x, older be y. x + y = 120000. Younger son (12) gets amount at 18 (6 years interest). Older son (14) gets amount at 18 (4 years interest). x(1 + 0.05*6) = y(1 + 0.05*4) => 1.3x = 1.2y => y = 1.3x/1.2 = 13x/12. x + 13x/12 = 120000 => 25x/12 = 120000 => x = 120000 * 12 / 25 = 57600.

Multiple choice

A computer is sold either for Rs.19200 cash or for Rs.4800 cash down payment together with five equal monthly installments. If the rate of interest charged is 12% per annum, then the amount of each installment (nearest to a rupee) is:

  1. Rs.2880

  2. Rs.2965

  3. Rs.2896

  4. Rs.2990

  5. Rs.3016
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

The cash price is 19200. The down payment is 4800, leaving a balance of 14400 to be paid in 5 installments. Using the formula for installments with interest, the monthly payment is calculated as approximately 2965.

Multiple choice

The compound interest earned by Suresh on a certain amount at the end of 2 years at the rate of 8% per annum was Rs. 1414.40. What was the total amount that Suresh got back at the end of 2 years in the form of principal plus interest earned?

  1. Rs. 9414.40

  2. Rs. 9914.40

  3. Rs. 9014.40

  4. Rs. 8914.40
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

CI = P * ((1+r/100)^n - 1). 1414.40 = P * ((1.08)^2 - 1) = P * (1.1664 - 1) = P * 0.1664. P = 1414.40 / 0.1664 = 8500. Total amount = P + CI = 8500 + 1414.40 = 9914.40.

Multiple choice

Sonali invests money in three different schemes for 6 years, 10 years and 12 years at 10% p.a. 12% p.a. and 15% p.a. at simple interest, respectively. At the completion of each scheme, she gets the same interest. What is the ratio of her investments?

  1. 6 : 3 : 2

  2. 3 : 2 : 1

  3. 3 : 4 : 5

  4. 2 : 3 : 6
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Interest = P * R * T / 100. Since interest is equal, P1*10*6 = P2*12*10 = P3*15*12. This gives 60*P1 = 120*P2 = 180*P3. Dividing by 60, we get P1 = 2*P2 = 3*P3, so the ratio P1:P2:P3 is 6:3:2.

Multiple choice

Which of the following statements is/are true? Statement 1: The value of a car depreciates at the rate of 10% per year. A car which was bought three years ago is now worth Rs. 4,73,850. Its original price was Rs. 6,50,000. Statement 2: In fixed deposit, a bank gives 10% interest compounded annually for senior citizens. In 6 years, it will double a sum of money.

  1. Only Statement 1

  2. Only Statement 2

  3. Both Statement 1 and Statement 2

  4. Neither Statement 1 nor Statement 2
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

For Statement 1, the depreciated value is 650000 * (0.9)^3 = 650000 * 0.729 = 473850. This is correct. For Statement 2, using the rule of 72, 72/10 = 7.2 years, so it will not double in 6 years.

Multiple choice

Simple interest on a sum of money for 1 year at 12% per annum is Rs. 1200. What will be the compound interest when compounded half-yearly on that sum at the same rate for the same period?

  1. Rs. 1236

  2. Rs. 1326

  3. Rs. 11,236

  4. Rs. 13,260
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

SI = 1200 for 1 year at 12% means Principal = 1200 / 0.12 = 10000. For compound interest half-yearly at 12% per annum (6% per half-year) for 1 year (2 periods): CI = 10000 * (1.06)^2 - 10000 = 10000 * 1.1236 - 10000 = 1236.