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

Kruti took some loan at $6\%$ per annum simple interest during the first year with an increase of $0.5\%$ for each year. After $4$ years she paid Rs. $3375$ as interest. How much was the loan ?
  1. Rs. $12500$
  2. Rs. $33250$
  3. Rs. $15800$

  4. Cannot be determined
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Simple interest for 4 years with increasing rates: Year 1 = 6%, Year 2 = 6.5%, Year 3 = 7%, Year 4 = 7.5%. Total interest rate = 6 + 6.5 + 7 + 7.5 = 27%. If P is the principal, 0.27 * P = 3375, so P = 3375 / 0.27 = 12500.

Multiple choice

A man wants to divide a sum of Rs $37500$ among his son and daughter aged $12$ years and $14$ years respectively in such a way that on attaining the age of $18$ years each gets the same amount at $5\%$ p.a. simple interest. The son's share is
  1. Rs. $19500$
  2. Rs. $18000$
  3. Rs. $15000$
  4. Rs. $20000$
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let shares be S and D. S(1 + 0.05*6) = D(1 + 0.05*4) => 1.3S = 1.2D => D = 13/12 S. S + 13/12 S = 37500 => 25/12 S = 37500 => S = 18000.

Multiple choice

A sum of Rs. $10000$ is lent partly at $8\%$ and remaining at $10\%$ per annum. If the yearly interest on the average is $9.2\%$, what are the two parts?
  1. Rs. $4000$ and Rs. $6000$
  2. Rs. $3000$ and Rs. $7000$
  3. Rs. $2000$ and Rs. $8000$
  4. Rs.$1000$ and Rs. $8000$
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let x be invested at 8%, so 10000 - x is invested at 10%. The weighted average equation 0.08x + 0.10(10000 - x) = 920 gives x = Rs. 4000, leaving Rs. 6000.

Multiple choice

A sum of $Rs.\,5000$ was lent partly at $6\%$ and partly at $9\%$ simple interest. If the total interest received after $1$ year was $Rs.\,390$, what was the ratio in which the money was lent at $6\%$ and $9\%$?
  1. $1\,\colon\,5$.
  2. $2\,\colon\,5$.
  3. $2\,\colon\,3$.
  4. $1\,\colon\,3$.
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Let x be the amount at 6 percent and (5000-x) at 9 percent. 0.06x + 0.09(5000-x) = 390. 0.06x + 450 - 0.09x = 390. -0.03x = -60. x = 2000. The other part is 3000. Ratio = 2000:3000 = 2:3.

Multiple choice

Pratap borrowed a sum of money from Arun at simple interest, at the rate of $12\%\,p.a.$ for the first three years, $16\%\,p.a.$ for the next five years and $20\%\,p.a.$ for a period beyond eight years. If at the end of $11$ years, the total interest is $Rs.\,6080$ more than the sum, what was the sum borrowed?
  1. $\;Rs.\,3000$.
  2. $\;Rs.\,8000$.
  3. $\;Rs.\,7000$.
  4. $\;Rs.\,4000$.
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Let the sum be P. Interest = (P * 0.12 * 3) + (P * 0.16 * 5) + (P * 0.20 * 3) = 0.36P + 0.80P + 0.60P = 1.76P. We are given 1.76P = P + 6080, so 0.76P = 6080. P = 6080 / 0.76 = 8000.

Multiple choice

A person invests money in three different schemes for $6$ years, $10$ years and $12$ years at $10\%,12\%$ and $15\%$ simple interest respectively. At the completion of each scheme, he gets the same interest. What is the ratio of his investments?
  1. $\;6\,\colon\,3\,\colon\,2$.
  2. $\;2\,\colon\,3\,\colon\,4$.
  3. $\;5\,\colon\,2\,\colon\,1$.
  4. $\;7\,\colon\,4\,\colon\,2$.
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Let investments be I1, I2, I3. Interest is equal: I1*0.10*6 = I2*0.12*10 = I3*0.15*12. 0.6*I1 = 1.2*I2 = 1.8*I3. Dividing by 0.6: I1 = 2*I2 = 3*I3. Ratio I1:I2:I3 = 1 : 1/2 : 1/3 = 6 : 3 : 2.

Multiple choice

$Rs.\,800$ becomes $Rs.\,956$ in $3$ years at a certain rate of simple interest. If the rate of interest is increased by $4\%$, what will $Rs.\,800$ amount to in $3$ years?
  1. $\;Rs.\,1020.80$
  2. $\;Rs.\,1025$
  3. $\;Rs.\,1052$
  4. $\;Rs.\,1050$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Original interest = 956 - 800 = 156 for 3 years. Rate r = (156 * 100) / (800 * 3) = 6.5%. New rate = 6.5 + 4 = 10.5%. New interest = (800 * 10.5 * 3) / 100 = 252. New amount = 800 + 252 = 1052.