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

Rohit took a loan of Rs 20000 to purchase a LCD TV set from a finance company. He promised to make the payment after three years. The company charges compound interest at the rate of 10% per annum for the same. Suddenly the company announced the rate of interest as 15% per annum for the last one year of the loan period. What extra amount will Rohit pay due to this announcement of the new rate of interest?

  1. Rs 7830

  2. Rs 4410

  3. Rs 1210

  4. Rs 6620
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Original amount after 3 years at 10% is 20000 * (1.1)^3 = 26620. New amount is 20000 * (1.1)^2 * 1.15 = 27830. The difference is 27830 - 26620 = 1210.

Multiple choice

A certain sum of money amounts to Rs. 1008 in 2 years and to Rs. 1164 in $3\, \displaystyle \frac{1}{2}$ years. Find the rate of interest.

  1. 11%

  2. 12%

  3. 13%

  4. 14%
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Amount in 2 years = 1008. Amount in 3.5 years = 1164. Interest for 1.5 years = 1164 - 1008 = 156. Interest for 1 year = 156 / 1.5 = 104. Interest for 2 years = 208. Principal = 1008 - 208 = 800. Rate = (Interest * 100) / (Principal * Time) = (104 * 100) / (800 * 1) = 13%.

Multiple choice

Consider the following statements: If a sum of money is lent at simple interest, then the 1. Money gets doubled in 5 years if the rate of interest is $16 \displaystyle \frac{2}{3}$% 2. Money gets doubled in 5 years if the rate of interest is 20% 3. Money becomes four times in 10 years if it gets doubled in 5 years Of these statements

  1. 1 and 3 are correct

  2. 2 alone is correct

  3. 3 alone is correct

  4. 2 and 3 are correct
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

1: SI = P*R*T/100. For doubling, SI = P. P = P*R*5/100 => R = 20%. Statement 1 is false. 2: R = 20% leads to doubling in 5 years. Statement 2 is true. 3: If it doubles in 5 years, it becomes 4 times in 15 years (not 10). Statement 3 is false.

Multiple choice

If the simple interest on a certain sum for 15 months at $7\, \displaystyle \frac{1}{2}$% per annum exceeds the simple interest on the same sum for 8 months at $12\, \displaystyle \frac{1}{2}$% per annum by Rs.32.50, then the sum (in Rs.) is

  1. Rs. 3000

  2. Rs. 3060

  3. Rs. 3120

  4. Rs. 3250
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

The first interest equals 9.375% of the principal, while the second equals 8.333% of the principal. Their difference is 1.041667% of the principal, so 0.01041667P = 32.50, giving P = 3120 rupees.

Multiple choice

Divide Rs. 2379 into 3 parts so that their amounts after 2, 3 and 4 years respectively may be equal, the rate of interest being 5% per annum at simple interest. The first part is

  1. Rs. 759

  2. Rs. 792

  3. Rs. 818

  4. Rs. 828
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Let the parts be x, y, z. Amounts are x(1 + 0.05*2), y(1 + 0.05*3), z(1 + 0.05*4) = 1.1x = 1.15y = 1.2z. x:y:z = 1/1.1 : 1/1.15 : 1/1.2 = 1/110 : 1/115 : 1/120. Multiplying by common factors leads to the ratio 276:264:253. Sum = 793 parts. 2379 / 793 = 3. First part = 276 * 3 = 828.

Multiple choice

Peter invested an amount of Rs. 12,000 at the rate of 10 % p.a. simple interest and. another amount at the rate of 20 % p.a. simple interest. The total interest earned at the end of one year on the total amount invested became 14 % p.a. Find the total amount invested.
  1. $Rs. 20,000$
  2. $Rs.22,000$
  3. $Rs. 24,000$
  4. $Rs. 25,000$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let the second amount be x. Total interest = 0.10 * 12000 + 0.20 * x = 0.14 * (12000 + x). 1200 + 0.2x = 1680 + 0.14x -> 0.06x = 480 -> x = 8000. Total amount = 12000 + 8000 = 20000.

Multiple choice

A person takes a loan of Rs. 200 at 5% simple interest. He returns Rs. 100 at the end of 1 year. In order to clear his dues at the end of two years, he would pay

  1. Rs. 105

  2. Rs. 110

  3. Rs. 115

  4. Rs.115.50
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Principal = 200, Rate = 5%. Interest for 1st year = 200 * 0.05 = 10. Total amount = 210. He pays 100, remaining balance = 110. Interest for 2nd year on 110 = 110 * 0.05 = 5.50. Total to pay = 110 + 5.50 = 115.50.