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Find the compound interest on Rs. 1000 at the rate of 20% per annum for 18 month when interest is compounded half yearly.

A. Rs. 331

B. Rs. 1331

C. Rs. 320

D. Rs. 325

E. None of these

Answer: Option A

Solution (By Examveda Team)

$$\eqalign{ & {\text{Given,}}\,{\text{Principal}},\,P = Rs.\,1000 \cr & {\text{Compoind}}\,{\text{rate}},\,R = 20\% \,{\text{per}}\,{\text{annum}} \cr & = \frac{{20}}{2} = 10\% \,{\text{half - yearly}} \cr & {\text{Time}} = 18\,{\text{month}} = 3\,{\text{half - years}} \cr & {\text{Amount}}, \cr & A = \left\{ {P \times {{\left[ {1 + \left( {\frac{R}{{100}}} \right)} \right]}^n}} \right\} \cr & = \left\{ {1000 \times {{\left[ {1 + \left( {\frac{{10}}{{100}}} \right)} \right]}^3}} \right\} \cr & = { {\frac{{1000 \times 11 \times 11 \times 11}}{{10 \times 10 \times 10}}} } \cr & A = Rs.\,1331 \cr & {\text{Hence,}}\,{\text{compound}}\,{\text{interest}} = Rs.\,331 \cr} $$

This Question Belongs to Arithmetic Ability >> Interest

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Comments (7)

  1. Otaku Gaymer
    Otaku Gaymer:
    1 year ago

    To find the compound interest, we can use the formula:

    CI = P x (1 + r/n)^(nt) - P

    Where:
    CI = Compound Interest
    P = Principal Amount (Rs. 1000)
    r = Annual interest rate (20% = 0.20)
    n = Number of times interest is compounded per year (2, since it's compounded half-yearly)
    t = Time in years (18 months = 1.5 years)

    Plugging in the values:

    CI = 1000 x (1 + 0.20/2)^(2*1.5) - 1000
    CI = 1000 x (1.10)^3 - 1000
    CI = 1331 - 1000
    CI = Rs. 331

    So, the compound interest is Rs. 331.

    The total amount after 18 months will be Rs. 1000 + Rs. 331 = Rs. 1331.

  2. Ithi Arun
    Ithi Arun:
    4 years ago

    could someone tell me how 18months is 3 half years

  3. MD MIRAZ
    MD MIRAZ:
    4 years ago

    or any simplr formula??

  4. Deblina Roy
    Deblina Roy:
    5 years ago

    I have 260

  5. Rashed Hussaini
    Rashed Hussaini:
    8 years ago

    I solved Find the amount and compound interest on rs 16000 for 1.5 years at 10% per annum the interest begin compounded half yearly? and got answer as (Compound interest:rup 38000)

    Thanks.
    Syed Rashed.

  6. Kumar Chandan
    Kumar Chandan:
    9 years ago

    @Nilesh, Interest is compounded half yearly.
    And, In half yearly Interest , rate is taken as half of the original rate.
    Here, Original rate is 20% but, it is compounded half yearly so it will become half i.e. 10%.

    Now, do your calculation, you will get the answer.

  7. Nilesh Dharecha
    Nilesh Dharecha:
    9 years ago

    A= p ( 1 + r|100)n
    A= 1000( 1+ 20| 100) テモテつウ
    1000 ( 1.2)テモテつウ
    1000 ( 1.728)
    1000テャテッツソツス 1.728
    Ans A= 1728
    How get the ans 331 plz help me

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