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 principal sum? P : The sum amounts to Rs. $690$ in $3$ yrs at Simple Interest. Q : The sum amounts to Rs. $750$ in $5$ yrs at Simple interest. R : The rate of interest is $5\%$ per annum.

  1. P & Q will give the answer

  2. R & Q will give the answer

  3. P & R will give the answer

  4. Any two will give the answer
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

Simple interest I = P * R * T / 100. P and Q provide two equations with two variables (P and R), allowing us to solve for P. R and Q provide two equations with two variables (P and T), allowing us to solve for P. P and R provide one equation with two variables (P and T), but R is known, so we can solve for P. Thus, any two statements are sufficient.

Multiple choice

Braun invested a certain sum of money at $8\%$ per annum simple interest for "$n$" years. At the end of "$n$" years, Braun got back $4$ times his original investment. What is the value of $ n$?
  1. $35.5$
  2. $36.5$
  3. $37.5$
  4. $38.5$
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Simple interest formula is I = P * r * n / 100. If the total amount is 4 times the principal, the interest earned is 3 times the principal. So, 3P = P * 8 * n / 100, which simplifies to 3 = 0.08n, so n = 3 / 0.08 = 37.5.