Simple interest


  1. The amount 2,100 became ₹2,352 in 2 years at simple interest. If the interest rate is decreased by 1%, what is the new interest ?









  1. View Hint View Answer Discuss in Forum

    As per the given in question ,
    S.I. = Amount - Principal = 2352 – 2100 = ₹ 252

    Rate =
    Interest × 100
    Principal × Time

    Rate =
    252 × 100
    = 6% per annum
    2100 × 2

    New rate = 5%

    Correct Option: A

    As per the given in question ,
    S.I. = Amount - Principal = 2352 – 2100 = ₹ 252

    Rate =
    Interest × 100
    Principal × Time

    Rate =
    252 × 100
    = 6% per annum
    2100 × 2

    New rate = 5%
    ∴ S.I. =
    252 × 5
    = ₹ 210
    6


  1. ₹800 amounts to ₹920 in 3 years at simple interest. If the interest rate is increased by 3%, it would amount to









  1. View Hint View Answer Discuss in Forum

    Given that , Amount = ₹ 920 and Principal = ₹ 800
    ∴ S.I. = Amount - Principal = ₹ (920 – 800) = ₹ 120

    ∴ Rate =
    Interest × 100
    Principal × Time

    Rate =
    120 × 100
    = 5% per annum
    800 × 3

    New rate = 8% per annum

    Correct Option: D

    Given that , Amount = ₹ 920 and Principal = ₹ 800
    ∴ S.I. = Amount - Principal = ₹ (920 – 800) = ₹ 120

    ∴ Rate =
    Interest × 100
    Principal × Time

    Rate =
    120 × 100
    = 5% per annum
    800 × 3

    New rate = 8% per annum
    ∴ SI =
    800 × 8 × 3
    = ₹ 192
    100

    ∴ Amount = Principal + SI = (800 + 192) = ₹ 992



  1. A sum of 2,400 amounts to ₹3,264 in 4 years at a certain rate of simple interest. If the rate of interest is increased by 1%, the same sum in the same time would amount to









  1. View Hint View Answer Discuss in Forum

    Here , Principal = 2,400 and Amount = ₹3,264
    S.I. = 3264 – 2400 = ₹ 864

    Rate =
    S.I. × 100
    Principal × Time

    Rate =
    864 × 100
    = 9% per annum
    2400 × 4

    New rate = 10% per annum

    Correct Option: D

    Here , Principal = 2,400 and Amount = ₹3,264
    S.I. = 3264 – 2400 = ₹ 864

    Rate =
    S.I. × 100
    Principal × Time

    Rate =
    864 × 100
    = 9% per annum
    2400 × 4

    New rate = 10% per annum
    ∴ SI =
    2400 × 10 × 4
    = ₹ 960
    100

    ∴ Amount = Principal + SI = 2400 + 960 = 3360


  1. A sum was lent at simple interest at a certain rate for 2 years. Had it been lent at 3% higher rate, it would have fetched ₹300 more. The original sum of money was :









  1. View Hint View Answer Discuss in Forum

    If the principal be p, then
    We can find the required answer with the help of given formula ,

    ∴ SI =
    P × R × T
    100

    p × 3 × 2
    = 300
    100

    ⇒ p =
    300 × 100
    = ₹ 5000
    3 ⇒ 2

    Second method to solve this question :
    P1 = P, R1 = R, T1 = 2.
    P2 = P, R2 = R + 3, T2 = 2 , S.I.= ₹ 300
    ∴ SI =
    P2 × R2 × T2 - P1 × R1 × T1
    100

    300 =
    P × (R + 3) × 2 - PR2
    100

    Correct Option: A

    If the principal be p, then
    We can find the required answer with the help of given formula ,

    ∴ SI =
    P × R × T
    100

    p × 3 × 2
    = 300
    100

    ⇒ p =
    300 × 100
    = ₹ 5000
    3 ⇒ 2

    Second method to solve this question :
    P1 = P, R1 = R, T1 = 2.
    P2 = P, R2 = R + 3, T2 = 2 , S.I.= ₹ 300
    ∴ SI =
    P2 × R2 × T2 - P1 × R1 × T1
    100

    300 =
    P × (R + 3) × 2 - PR2
    100

    300 =
    6P
    100

    P = ₹ 5000



  1. A sum of money was invested at a certain rate of simple interest for 2 years . Had it been invested at 1% higher rate, it would have fetched ₹24 more inter-est. The sum of money is :









  1. View Hint View Answer Discuss in Forum

    Given that , SI = ₹ 24 , R = 1% , T = 2 years
    Let Principal = P
    We know that ,

    SI =
    P × R × T
    100

    P × 1 × 2
    = 24
    100

    P =
    2400
    = ₹ 1200
    2

    Second method to solve this question :
    P1 = P, R1 = R, T1 = 2.
    P2 = P, R2 = R + 1, T2 = 2 , S.I.= Rs. 24

    Correct Option: A

    Given that , SI = ₹ 24 , R = 1% , T = 2 years
    Let Principal = P
    We know that ,

    SI =
    P × R × T
    100

    P × 1 × 2
    = 24
    100

    P =
    2400
    = ₹ 1200
    2

    Second method to solve this question :
    P1 = P, R1 = R, T1 = 2.
    P2 = P, R2 = R + 1, T2 = 2 , S.I.= Rs. 24
    24 =
    P(R + 1) 2 - PR2
    100

    2400 = 2PR + 2P – 2PR
    P = ₹ 1200