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 difference between the simple interest and the compound interest on a certain sum of money for 2 years at 15% per annum, if the simple interest on the sum at 10% per annum for a period of 2 years be Rs. 75?

  1. Rs. 7.3

  2. Rs. 6.7

  3. Rs. 8.4

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

Simple interest on sum P at 10% for 2 years = 75 => P * 0.1 * 2 = 75 => P = 375. CI for 2 years at 15% = P * ((1.15)^2 - 1) = 375 * (1.3225 - 1) = 375 * 0.3225 = 120.9375. SI for 2 years at 15% = 375 * 0.15 * 2 = 112.5. Difference = 120.9375 - 112.5 = 8.4375.

Multiple choice

Atul borrowed a sum of Rs. 4800 from Rahul at a rate of 9% per annum for 3 years. He added an amount of Rs. 1000 to the borrowed money and lent it to Chandan at the same rate of interest for 3 years compounded annually. After 3 years, what was the gain/loss for Atul?

  1. Rs. 250

  2. Rs. 398

  3. Rs. 415

  4. Rs. 537

  5. Rs. 1415
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Atul borrows 4800 at 9% SI for 3 years: Interest = 4800 * 0.09 * 3 = 1296. Total repayment = 6096. Atul lends 5800 (4800 + 1000) at 9% CI for 3 years: Amount = 5800 * (1.09)^3 = 5800 * 1.295029 = 7511.17. Gain = 7511.17 - 6096 - 1000 = 415.17.

Multiple choice

A sum of Rs. 1,300 is lent in two parts so that simple interest on the first part for three years at 5% may be equal to simple interest on the second part for 4 years at 6%. Find the sum lent on the first part.

  1. Rs. 800

  2. Rs. 900

  3. Rs. 750

  4. Rs. 589

  5. Rs. 850
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the parts be x and 1300-x. Interest 1 = x * 3 * 0.05 = 0.15x. Interest 2 = (1300-x) * 4 * 0.06 = 0.24(1300-x). Setting them equal: 0.15x = 312 - 0.24x, so 0.39x = 312, x = 800.

Multiple choice

Abhijit invested an amount with company X for two years at simple interest rate 15 pcpa. He invested the entire amount obtained from company X after two years with company Y at compound interest rate 12 pcpa for two years. If the amount finally received by him was Rs. 81536, what was the amount (in Rs.) invested by him originally with company X?

  1. 65000

  2. 60000

  3. 56000

  4. 50000

  5. 45000
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let P be principal. After 2 years SI at 15%: A = P(1 + 0.15*2) = 1.3P. This amount is invested at 12% CI for 2 years: 1.3P * (1.12^2) = 81536. 1.3P * 1.2544 = 81536. 1.63072P = 81536. P = 81536 / 1.63072 = 50000.

Multiple choice

A money-lender borrows money at 4% per annum and pays the compound interest at the end of the year. He lends it at 6% p.a. compounded half-yearly and receives the interest at the end of the year. In this way, he gains Rs. 104.50 in that year. How much money does he borrow?

  1. Rs. 4850

  2. Rs. 4500

  3. Rs. 5000

  4. Rs. 5200

  5. Rs. 6000
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The money-lender borrows at 4% compounded annually, so the cost is 0.04P. He lends at 6% compounded half-yearly, which is equivalent to an annual rate of (1 + 0.06/2)^2 - 1 = 1.03^2 - 1 = 0.0609, or 6.09%. The gain is 0.0609P - 0.04P = 0.0209P = 104.50. Solving for P gives 104.50 / 0.0209 = 5000.

Multiple choice

Jack deposited Rs. 20,000 at the rate of 10% per annum for 5 years and on the other side, Charlie deposited Rs. 22,000 at the rate of 8% per annum for 4 years. What would be the difference of the simple interest which they both would get?

  1. Rs. 2960

  2. Rs. 2460

  3. Rs. 2100

  4. Rs. 2000

  5. Rs. 1840
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Jack's interest = (20000 * 10 * 5) / 100 = 10000. Charlie's interest = (22000 * 8 * 4) / 100 = 7040. The difference is 10000 - 7040 = 2960.