Compound Interest


  1. The sum of money which becomes ₹ 2420 at 10 % rate of compound interest after two years is









  1. View Hint View Answer Discuss in Forum

    Given Here , Amount ( A ) = ₹ 2420 , P = ? , Rate ( R ) = 10% , Time = 2 years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒  2420 = P1 +
    10
    2
    100

    ⇒ 2420 = P1 +
    1
    2 = P
    11
    2
    1010

    Correct Option: A

    Given Here , Amount ( A ) = ₹ 2420 , P = ? , Rate ( R ) = 10% , Time = 2 years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒  2420 = P1 +
    10
    2
    100

    ⇒ 2420 = P1 +
    1
    2 = P
    11
    2
    1010

    ⇒  P =
    2420 × 10 × 10
    = Rs. 2000
    11 × 11


  1. When principal = ₹ S, rate of interest = 2r % p.a, then a person will get after 3 years at compound interest









  1. View Hint View Answer Discuss in Forum

    Here , Amount ( A ) = ? , Principal (P) = ₹ S , Rate ( R ) = 2r% per annum , Time = 3 years
    As we know that ,

    ∴ Amount = P1 +
    R
    T
    100

    Correct Option: C

    Here , Amount ( A ) = ? , Principal (P) = ₹ S , Rate ( R ) = 2r% per annum , Time = 3 years
    As we know that ,

    ∴ Amount = P1 +
    R
    T
    100

    Amount = S1 +
    2r
    3 = S1 +
    r
    3
    10050



  1. Rekha invested a sum of ₹ 12000 at 5% per annum compound interest. She received an amount of ₹ 13230 after n years. Find n.









  1. View Hint View Answer Discuss in Forum

    Given that , Amount ( A ) = ₹ 13230 , P = ₹ 12000 , Rate ( R ) = 5% , Time = n years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒ 13230 = 120001 +
    5
    n
    100

    13230
    = 1 +
    1
    n
    1200020

    441
    =
    21
    n
    40020

    Correct Option: D

    Given that , Amount ( A ) = ₹ 13230 , P = ₹ 12000 , Rate ( R ) = 5% , Time = n years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒ 13230 = 120001 +
    5
    n
    100

    13230
    = 1 +
    1
    n
    1200020

    441
    =
    21
    n
    40020

    21
    n =
    21
    2
    2020

    ⇒  n = 2 years


  1. A sum of Rs. 2420 is accumulated in 2 years at 10% compund interest on a certain amount. Then the original amount is :









  1. View Hint View Answer Discuss in Forum

    Let the principal be Rs. P.
    Given in question , Amount ( A ) = Rs. 2420 , Rate ( R ) = 10% , Time = 2 years
    Using the given formula ,

    ∴ A = P1 +
    R
    T
    100

    ⇒  2420 = P1 +
    10
    2
    100

    ⇒  2420 = P × 1 +
    10
    2
    100

    ⇒  2420 = P
    11
    2
    10

    Correct Option: B

    Let the principal be Rs. P.
    Given in question , Amount ( A ) = Rs. 2420 , Rate ( R ) = 10% , Time = 2 years
    Using the given formula ,

    ∴ A = P1 +
    R
    T
    100

    ⇒  2420 = P1 +
    10
    2
    100

    ⇒  2420 = P × 1 +
    10
    2
    100

    ⇒  2420 = P
    11
    2
    10

    ⇒  P =
    2420 × 10 × 10
    = Rs. 2000
    11 × 11



  1. Two years ago, the value of my motorbike was ₹ 62500. If the value depreciates by 4% every year, now its value is









  1. View Hint View Answer Discuss in Forum

    Here , P = ₹ 62500 , Rate ( R ) = 4% , Time = 2 years
    Using the given formula ,

    Present worth of bike = P 1 −
    R
    T
    100

    Present worth of bike = 62500 1 −
    4
    2
    100

    Present worth of bike = 62500 1 −
    1
    2
    25

    Correct Option: B

    Here , P = ₹ 62500 , Rate ( R ) = 4% , Time = 2 years
    Using the given formula ,

    Present worth of bike = P 1 −
    R
    T
    100

    Present worth of bike = 62500 1 −
    4
    2
    100

    Present worth of bike = 62500 1 −
    1
    2
    25

    Present worth of bike = 62500
    25 − 1
    2
    25

    ⇒ Present worth of bike =
    62500 × 24 × 24
    = ₹ 57600
    25 × 25