Compound Interest


  1. The compound interest on Rs. 1000 at 10% per annum for 3 years in (Rs.) is :









  1. View Hint View Answer Discuss in Forum

    Here , Principal ( P ) = Rs. 1000 , Compound Interest ( CI ) = ? , Rate ( R ) = 10% , Time = 3 years
    Using the given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    C.I. = 1000 1 +
    10
    3 − 1
    100

    C.I. = 1000 1 +
    1
    3 − 1
    10

    C.I. = 1000
    11
    3 − 1
    10

    Correct Option: B

    Here , Principal ( P ) = Rs. 1000 , Compound Interest ( CI ) = ? , Rate ( R ) = 10% , Time = 3 years
    Using the given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    C.I. = 1000 1 +
    10
    3 − 1
    100

    C.I. = 1000 1 +
    1
    3 − 1
    10

    C.I. = 1000
    11
    3 − 1
    10

    C.I. = 1000
    1331
    − 1
    1000

    ⇒ C.I. =
    1000 × 331
    = Rs. 331
    1000


  1. What would be the compound interest of Rs. 25000 for 2 years at the rate of 5% per annum ?









  1. View Hint View Answer Discuss in Forum

    Given in question , Principal ( P ) = Rs. 25000 , Compound Interest ( CI ) = ? , Rate ( R ) = 5% , Time = 2 years
    We can find required answer with the help of given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    C.I. = 25000 1 +
    5
    2 − 1
    100

    C.I. = 25000 1 +
    1
    2 − 1
    20

    C.I. = 25000
    21
    2 − 1
    20

    C.I. = 25000
    441
    − 1
    400

    Correct Option: B

    Given in question , Principal ( P ) = Rs. 25000 , Compound Interest ( CI ) = ? , Rate ( R ) = 5% , Time = 2 years
    We can find required answer with the help of given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    C.I. = 25000 1 +
    5
    2 − 1
    100

    C.I. = 25000 1 +
    1
    2 − 1
    20

    C.I. = 25000
    21
    2 − 1
    20

    C.I. = 25000
    441
    − 1
    400

    C.I. = 2500
    441 − 400
    400

    C.I. =
    25000 × 41
    = Rs. 2562.5
    400



  1. The compound interest on a certain sum of money for 2 years at 10% per annum is ₹ 420. The simple interest on the same sum at the same rate and for the same time will be









  1. View Hint View Answer Discuss in Forum

    Given that , Compound Interest ( CI ) = ₹ 420 , Rate ( R ) = 10% , Time = 2 years
    If the principal be P then

    C.I. = P 1 +
    R
    T − 1
    100

    ⇒  420 = P 1 +
    10
    2 − 1
    100

    ⇒  420 = P
    121 − 100
    100

    ⇒  420 =
    P × 21
    100

    ⇒  P =
    420 × 100
    = ₹ 2000
    21

    ∴  S.I. =
    PRT
    100

    S.I. =
    2000 × 10 × 2
    = ₹ 400
    100

    We can find required answer with the help of given formula :
    Here, C.I. = Rs. 420 , R = 10% , S.I. = ?
    C.I.= S.I.1 +
    R
    200

    Correct Option: D

    Given that , Compound Interest ( CI ) = ₹ 420 , Rate ( R ) = 10% , Time = 2 years
    If the principal be P then

    C.I. = P 1 +
    R
    T − 1
    100

    ⇒  420 = P 1 +
    10
    2 − 1
    100

    ⇒  420 = P
    121 − 100
    100

    ⇒  420 =
    P × 21
    100

    ⇒  P =
    420 × 100
    = ₹ 2000
    21

    ∴  S.I. =
    PRT
    100

    S.I. =
    2000 × 10 × 2
    = ₹ 400
    100

    We can find required answer with the help of given formula :
    Here, C.I. = Rs. 420 , R = 10% , S.I. = ?
    C.I.= S.I.1 +
    R
    200

    420 = S.I.1 +
    10
    200

    420 = S.I.
    210
    200

    S.I. =
    420 × 200
    = ₹ 400
    210


  1. The sum for 2 years gives a compound interest of Rs. 3225 at the rate of 15% per annum. The sum is









  1. View Hint View Answer Discuss in Forum

    Given that , Principal ( P ) = ? , Compound Interest ( CI ) = Rs. 3225 , Rate ( R ) = 15% , Time = 2 years
    Using the given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    ⇒  3225 = P 1 +
    15
    2 − 1
    100

    ⇒  3225 = P 1 +
    3
    2 − 1
    20

    ⇒  3225 = P
    23
    2 − 1
    20

    ⇒ 3225 = P
    529
    − 1
    400

    Correct Option: A

    Given that , Principal ( P ) = ? , Compound Interest ( CI ) = Rs. 3225 , Rate ( R ) = 15% , Time = 2 years
    Using the given formula ,

    C.I. = P 1 +
    R
    T − 1
    100

    ⇒  3225 = P 1 +
    15
    2 − 1
    100

    ⇒  3225 = P 1 +
    3
    2 − 1
    20

    ⇒  3225 = P
    23
    2 − 1
    20

    ⇒ 3225 = P
    529
    − 1
    400

    ⇒ 3225 = P
    529 − 400
    400

    ⇒ 3225 = P ×
    129
    400

    ⇒  P =
    3225 × 400
    = Rs. 10000
    129



  1. In 3 years Rs. 3000 amounts to Rs. 3993 at x% compound interest, compounded annually. The value of x is









  1. View Hint View Answer Discuss in Forum

    Given in question , Amount ( A ) = Rs. 3993 , P = Rs. 3000 , Rate = x% , Time = 3 years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒ 3993 = 30001 +
    x
    3
    100

    ⇒ 
    3993
    = 1 +
    x
    3
    3000100

    ⇒ 
    1331
    = 1 +
    x
    3
    1000100

    ⇒ 
    11
    3 = 1 +
    x
    3
    10100

    ⇒ 1 +
    x
    =
    11
    10010

    Correct Option: A

    Given in question , Amount ( A ) = Rs. 3993 , P = Rs. 3000 , Rate = x% , Time = 3 years
    Using the given formula ,

    A = P1 +
    R
    T
    100

    ⇒ 3993 = 30001 +
    x
    3
    100

    ⇒ 
    3993
    = 1 +
    x
    3
    3000100

    ⇒ 
    1331
    = 1 +
    x
    3
    1000100

    ⇒ 
    11
    3 = 1 +
    x
    3
    10100

    ⇒ 1 +
    x
    =
    11
    10010

    ⇒ 
    x
    =
    11
    − 1 =
    1
    1001010

    ⇒ x =
    1
    ×100
    10

    Hence , x = 10% per annum