Simple Interest Questions and Answers

• 1. What will the ratio of simple interest earned by certain amount at the same rate of interest for 6 years and that for 9 years.

  1. Defined values
  2. Fixed values
  3. Default values
  4. None of the above
  5. 1:2
  6. 2:1
  7. 2:2
  8. 2:3

  Answer :

  Option

  Explanation:

  Let the principal be P and rate be R
  
  then
  
  \begin{aligned}
  \text{ratio = } [\frac{(\frac{P*R*6}{100})}{(\frac{P*R*9}{100})}] \\
  
  = \frac{6PR}{9PR} = 2:3
  \end{aligned}

• 2. A financier claims to be lending money at simple interest, But he includes the interest every six months for calculating the principal. If he is charging an interest of 10%, the effective rate of interest becomes.

  1. 10.25%
  2. 10%
  3. 9.25%
  4. 9%

  Answer :

  Option A

  Explanation:

  Let the sum is 100.
  
  As financier includes interest every six months., then we will calculate SI for 6 months, then again for six months as below:
  
  SI for first Six Months = (100*10*1)/(100*2) = Rs. 5
  
  Important: now sum will become 100+5 = 105
  
  SI for last Six Months = (105*10*1)/(100*2) = Rs. 5.25
  
  So amount at the end of year will be (100+5+5.25)
  = 110.25
  
  Effective rate = 110.25 - 100 = 10.25
  
  

• 3. In how many years Rs 150 will produce the same interest at 8% as Rs. 800 produce in 3 years at 9/2%

  1. 8
  2. 9
  3. 10
  4. 11

  Answer :

  Option B

  Explanation:

  Clue:
  Firstly we need to calculate the SI with prinical 800,Time 3 years and Rate 9/2%, it will be Rs. 108
  
  Then we can get the Time as
  
  Time = (100*108)/(150*8) = 9

• 4. A lent Rs. 5000 to B for 2 years and Rs 3000 to C for 4 years on simple interest at the same rate of interest and received Rs 2200 in all from both of them as interest. The rate of interest per annum is

  1. 9%
  2. 10%
  3. 11%
  4. 12%

  Answer :

  Option B

  Explanation:

  Let R% be the rate of simple interest then,
  
  from question we can conclude that
  
  \begin{aligned}
  (\frac{5000*R*2}{100}) + (\frac{3000*R*4}{100}) = 2200 \\
  
  <=> 100R + 120R = 2200 \\
  <=> R = 10\%
  
  
  \end{aligned}

• 5. A sum of money amounts to Rs 9800 after 5 years and Rs 12005 after 8 years at the same rate of simple interest. The rate of interest per annum is

  1. 9%
  2. 10%
  3. 11%
  4. 12%
  5. 73.17%
  6. 72.17%
  7. 71.17%
  8. 70.17%

  Answer :

  Option E

  Explanation:

  We can get SI of 3 years = 12005 - 9800 = 2205
  
  SI for 5 years = (2205/3)*5 = 3675 [so that we can get principal amount after deducting SI]
  
  Principal = 12005 - 3675 = 6125
  
  So Rate = (100*3675)/(6125*5) = 12%

• 6. If a sum of money doubles itself in 8 years at simple interest, the ratepercent per annum is

  1. 12
  2. 12.5
  3. 13
  4. 13.5
  5. Rs. 543.44 lakhs
  6. Rs. 544.44 lakhs
  7. Rs. 545.44 lakhs
  8. Rs. 546.44 lakhs

  Answer :

  Option F

  Explanation:

  Let sum = x then Simple Interest = x
  
  Rate = (100 * x) / (x * 8) = 12.5

• 7. Sahil took a loan for 6 years at the rate of 5% per annum on Simple Interest, If the total interest paid was Rs. 1230, the principal was

  1. 4100
  2. 4200
  3. 4300
  4. 4400

  Answer :

  Option A

  Explanation:

  \begin{aligned}
  \text{S.I.} = \frac{P*R*T}{100} \\
  => P = \frac{S.I. * 100}{R*T}
  \end{aligned}
  
  By applying above formula we can easily solve this question, as we are already having the simple interest.
  
  \begin{aligned}
  => P = \frac{1230 * 100}{6*5} \\
  => P = 4100
  \end{aligned}