True Discount


  1. The difference between the simple interest and the true discount on a certain sum of money for 2 years at 15 % per annum at simple interest is ₹45. Find the sum.











  1. View Hint View Answer Discuss in Forum

    Let the sum be ₹100.
    Given that :- Time = 2 years
    Rate = 15% per annum

    Simple Interest = ₹100 × 15 × 2= ₹30
    100

    True Discount = ₹100 × R × T
    100 + (R×T)
    True Discount = ₹100 × 15 × 2
    100 + (15×2)
    True Discount = ₹100 × 15 × 2 = ₹300
    100 + (15×2)13

    The difference between Simple Interest and True Discount is
    30 - 300= ₹90
    1313
    If the difference in S.I. and True Discount is ₹90,the sum = ₹100
    13

    Correct Option: B

    Let the sum be ₹100.
    Given that :- Time = 2 years
    Rate = 15% per annum

    Simple Interest = ₹100 × 15 × 2= ₹30
    100

    True Discount = ₹100 × R × T
    100 + (R×T)
    True Discount = ₹100 × 15 × 2
    100 + (15×2)
    True Discount = ₹100 × 15 × 2 = ₹300
    100 + (15×2)13

    The difference between Simple Interest and True Discount is
    30 - 300= ₹90
    1313
    If the difference in S.I. and True Discount is ₹90,the sum = ₹100
    13

    If the difference in S.I. and T.D. is ₹1,
    The sum = ₹100 x 13.
    10

    If the difference in S.I. and T.D. is ₹45,
    The sum = ₹100 × 13× 45 = ₹650.
    90


  1. If ₹21 is the true discount on ₹371 for a certain time, what is the true discount on the same amount for double that time, the rate being the same in both the cases?











  1. View Hint View Answer Discuss in Forum

    Here , Amount = ₹ 371 ,True discount = ₹ 21
    ₹21 is the interest on ₹( 371 - 21 ) = ₹350
    Present worth = ₹350

    Present worth × no of year × rate = True Discount
    100

    350 × no of year × rate = 21
    100
    ⇒ Number of year × rate = 2100= 6
    350

    ∴ Twice number of years × rate ( R x T )= 12
    Now, on ₹112, the True Discount is ₹12
    ∴ on ₹371, True Discount = ₹Amount × Rate × Time
    100 + ( Rate × Time )

    Correct Option: D

    Here ,( Sum Due ) Amount = ₹ 371 , True discount = ₹ 21
    ₹21 is the interest on ₹( 371 - 21 ) = ₹350
    Present worth = ₹350

    Present worth × no of year × rate = True Discount
    100

    350 × no of year × rate = 21
    100
    ⇒ Number of year × rate = 2100= 6
    350

    ∴ Twice number of years × rate ( R x T )= 12
    Now, on ₹112, the True Discount is ₹12
    ∴ on ₹371, True Discount = ₹Amount × Rate × Time
    100 + ( Rate × Time )

    True Discount = ₹12× 371
    112

    True Discount = ₹39.75



  1. If the simple interest on ₹2000 at 5 % p.a. is equal to the true discount on ₹2500 for the same time and at the same rate, the time is :











  1. View Hint View Answer Discuss in Forum

    Given :- True Discount ( T.D. ) = ₹500
    Rate = 5%
    Present Worth ( P.W. ) = ₹2000

    ∴ Time = True Discount × 100 Year
    Present Worth × Rate

    Correct Option: B

    Given :- True Discount ( T.D. ) = ₹500
    Rate = 5%
    Present Worth ( P.W. ) = ₹2000

    ∴ Time = True Discount × 100 Year
    Present Worth × Rate

    Time = 500×100 = 5 Year
    2000×5


  1. The true discount on a certain bill due for nine months at 4 % simple interest is ₹150. Find the amount of the bill.











  1. View Hint View Answer Discuss in Forum

    Given :- True Discount = ₹ 150 , Time = 9 months = ( 3/4 ) years

    Present worth ( P.W. ) = True Discount ×100 = ₹150 × 100
    R × T3/4 × 4

    Correct Option: A

    Given :- True Discount = ₹ 150 , Time = 9 months = ( 3/4 ) years

    Present worth ( P.W. ) = True Discount ×100 = ₹150 × 100
    R × T3/4 × 4

    Present worth = 5000
    ∴ Amount of the bill = Present worth + True discount
    Amount of the bill = ₹5000 + ₹150 = ₹5150.



  1. The True Discount on a certain sum of money due in 2 years is ₹1800 and the simple interest on the same amount is ₹2232. Find the sum.











  1. View Hint View Answer Discuss in Forum

    Given :- Simple interest = ₹ 1800 , True Discount = ₹ 2232

    Sum = Simple interest on the sum × True Discount (T.D.)
    Simple interest on the sum - True Discount (T.D.)
    Sum = ₹2232 × 1800
    2232 - 2232

    Correct Option: A

    Given :- Simple interest = ₹ 1800 , True Discount = ₹ 2232

    Sum = Simple interest on the sum × True Discount (T.D.)
    Simple interest on the sum - True Discount (T.D.)
    Sum = ₹2232 × 1800
    2232 - 2232
    Sum = ₹2232 × 1800
    432

    Sum = ₹9300.