Simple Interest Questions and Answers

• 8. At what rate percent per annum will the simple interest on a sum of money be 2/5 of the amount in 10 years

  1. 1%
  2. 2%
  3. 3%
  4. 4%

  Answer :

  Option D

  Explanation:

  Let sum = x
  Time = 10 years.
  S.I = 2x /5, [as per question]
  Rate =( (100 * 2x) / (x*5*10))%
  => Rate = 4%

• 9. There was simple interest of Rs. 4016.25 on a principal amount at the rate of 9%p.a. in 5 years. Find the principal amount

  1. Rs 7925
  2. Rs 8925
  3. Rs 7926
  4. Rs 7925

  Answer :

  Option B

  Explanation:

  \begin{aligned}
  P = \frac{S.I. * 100}{R*T}
  \end{aligned}
  
  So by putting values from our question we can get the answer
  
  \begin{aligned}
  P = \frac{4016.25 * 100}{9*5} \\
  = 8925
  \end{aligned}

• 10. 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 amount will Rs. 800 become in 3 years.

  1. Rs 1052
  2. Rs 1152
  3. Rs 1252
  4. Rs 1352

  Answer :

  Option A

  Explanation:

  S.I. = 956 - 800 = Rs 156
  
  \begin{aligned}
  R = \frac{156*100}{800*3} \\
  R = 6\frac{1}{2}\% \\
  
  \text{ New Rate = }6\frac{1}{2}+4 \\
  = \frac{21}{2} \% \\
  
  \text{ New S.I. = }800\times\frac{21}{2}\times{3}{100} \\
  = 252
  \end{aligned}
  
  Now amount will be 800 + 252 = 1052

• 11. A sum of Rs 12,500 amounts to Rs. 15,500 in the 4 years at the rate of simple interest. Find the rate percent

  1. 6 %
  2. 7 %
  3. 8 %
  4. 9 %

  Answer :

  Option A

  Explanation:

  \begin{aligned}
  \text{S.I.} = \frac{P*R*T}{100} \\
  => R = \frac{S.I. * 100}{P*T}
  \end{aligned}
  
  So, S.I = 15500 - 12500 = 3000.
  
  \begin{aligned}
  => R = \frac{3000 * 100}{12500*4} = 6\%
  \end{aligned}

• 12. If A lends Rs. 3500 to B at 10% p.a. and B lends the same sum to C at 11.5% p.a., then the gain of B (in Rs.) in a period of 3 years is

  1. Rs. 154.50
  2. Rs. 155.50
  3. Rs. 156.50
  4. Rs. 157.50

  Answer :

  Option D

  Explanation:

  We need to calculate the profit of B.
  It will be,
  SI on the rate B lends - SI on the rate B gets
  
  \begin{aligned}
  \text{Gain of B}\\ &= \frac{3500\times11.5\times3}{100} - \frac{3500\times10\times3}{100}\\
  = 157.50
  \end{aligned}

• 13. The simple interest on a certain sum of money at the rate of 5% p.a. for 8 years is Rs. 840. At what rate of intrest the same amount of interest can be received on the same sum after 5 years.

  1. 5%
  2. 6%
  3. 7%
  4. 8%

  Answer :

  Option D

  Explanation:

  Here firstly we need to calculate the principal amount, then we can calculate the new rate.
  
  \begin{aligned}
  P = \frac{S.I. * 100}{R*T} \\
  P = \frac{840 * 100}{5*8} \\
  P = 2100 \\
  
  \text{Required Rate = } \frac{840 * 100}{5*2100} \\
  R = 8\%\\
  
  \end{aligned}
  

• 14. Reema took a loan of Rs 1200 with simple interest for as many years as the rate of interest. If she paid Rs. 432 as interest at the end of the loan period, what was the rate of interest.

  1. 5%
  2. 6%
  3. 7%
  4. 8%

  Answer :

  Option B

  Explanation:

  Let rate = R% then Time = R years.
  \begin{aligned}
  => \frac{1200*R*R}{100}=432 \\
  => R^2 = 36 \\
  => R = 6\%
  
  \end{aligned}