True Discount


  1. If Rs. 10 be allowed as true discount on a bill of Rs. 110 due at the end of a certain time, then the discount allowed on the same sum due at the end of double the time is ?









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    S.I on Rs. (110 - 10) for a given time = Rs. 10
    S.I. on Rs. 100 for double the time = Rs. 20
    Sum = Rs. (100 + 20) = Rs. 120

    Correct Option: D

    S.I on Rs. (110 - 10) for a given time = Rs. 10
    S.I. on Rs. 100 for double the time = Rs. 20
    Sum = Rs. (100 + 20) = Rs. 120
    T.D. on Rs. 110 = Rs. (20/120) x 110 = Rs. 18.33


  1. Find the true discount on Rs. 39.69 due in 2 years reckoning compound interest at 5% ?









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    ∵ P.W. = 39.69 / (1 + 5 / 100)2
    = (3969 x 100 x 100) / (100 x 105 x 105) = Rs. 36

    Correct Option: A

    ∵ P.W. = 39.69 / (1 + 5 / 100)2
    = (3969 x 100 x 100) / (100 x 105 x 105) = Rs. 36
    ∴ True discount = Rs. 39.69 - 36 = Rs. 3.69



  1. Find the present worth of a bill of Rs. 2420 due 2 years later at 10% compound interest. Also find the true discount ?









  1. View Hint View Answer Discuss in Forum

    Here sum is put on compound interest,
    ∵ P.W. = A / (1 + r / 100)n = 2420 / (1 + 10 / 100)2 = 2420 x 100 / 121 = Rs. 2000
    ⇒ T.D. = P.W. - P

    Correct Option: A

    Here sum is put on compound interest,
    ∵ P.W. = A / (1 + r / 100)n = 2420 / (1 + 10 / 100)2 = 2420 x 100 / 121 = Rs. 2000
    ⇒ T.D. = P.W. - P
    ∴ True discount = 2420 - 2000 = Rs. 420


  1. If the discount on Rs. 3050 be equal to the simple interest on Rs. 3000 for the same time. Find the time, the rate of interest being 5% per annum ?









  1. View Hint View Answer Discuss in Forum

    ∵ 5 = {(3050 - 3000) / (3000 x T)} x 100
    ∴ T = 1/3 years = 4 months

    Correct Option: A

    ∵ 5 = {(3050 - 3000) / (3000 x T)} x 100
    ∴ T = 1/3 years = 4 months



  1. The true discount on a bill due 10 months hence at 6% per annum is Rs. 26.25. Then the amount of the bill is ?









  1. View Hint View Answer Discuss in Forum

    SI on rupees 100 for 10 months at 6% per annum = (100 x 10 x 6)/(12 x 100) = Rs. 5.
    ∴ Amount = 100 + 5 = 105.
    So true discount = 105 - 100 = Rs. 5

    Correct Option: A

    SI on rupees 100 for 10 months at 6% per annum = (100 x 10 x 6)/(12 x 100) = Rs. 5.
    ∴ Amount = 100 + 5 = 105.
    So true discount = 105 - 100 = Rs. 5

    So If TD = 5 then sum due = 100
    So, when TD = 26.25 the sum = (100 x 26.25) / 5 = Rs. 551.25