Compound Interest


  1. The compound interest on ₹ 30000 at 7% pa for a certain time is ₹4347. The time is









  1. View Hint View Answer Discuss in Forum

    Given, CI = ₹ 4347, P = ₹ 30000 and R = 7%
    By formula, CI = P[(1 + R/100)n - 1 ]
    ⇒ 4347 = 30000 [(1+7/100)n - 1]
    ⇒ (107/100)n = (4347/30000) + 1

    Correct Option: A

    Given, CI = ₹ 4347, P = ₹ 30000 and R = 7%
    By formula, CI = P[(1 + R/100)n - 1 ]
    ⇒ 4347 = 30000 [(1+7/100)n - 1]
    ⇒ (107/100)n = (4347/30000) + 1
    ⇒ (107/100)n = 34347/30000 = 11449/10000
    ⇒ (107/100)n = (107/100)2
    ∴ n = 2


  1. What is the difference between compound interest and simple interest for 2 yr on the sum of ₹ 1250 at 4% pa?









  1. View Hint View Answer Discuss in Forum

    Given, P = ₹ 1250, n = 2 yr and R = 4%
    According to the formula,
    Difference between compound interest and simple interest = PR2/1002

    Correct Option: C

    Given, P = ₹ 1250, n = 2 yr and R = 4%
    According to the formula,
    Difference between compound interest and simple interest = PR2/1002
    ∴ Required difference = (1250 x 4 x 4)/(100 x 100) = ₹ 2



  1. The difference between compound and simple rates of interest on ₹ 10000 for 3 yr at 5% per annum is









  1. View Hint View Answer Discuss in Forum

    Required difference = P(R/100)2 x [(300 + R)/100]
    = 10000(5/100)2 (305/100)

    Correct Option: A

    Required difference = P(R/100)2 x [(300 + R)/100]
    = 10000(5/100)2 (305/100)
    = 76.25


  1. A borrowed sum was paid in the two annual installments of ₹ 121 each. If the rate of compound interest is 10% pa, what sum was borrowed?









  1. View Hint View Answer Discuss in Forum

    According to the question,
    Borrowed sum = [121/{1/(1 + 10/100)}] + 121/(1 + 10/100)2

    Correct Option: B

    According to the question,
    Borrowed sum = [121/{1/(1 + 10/100)}] + 121/(1 + 10/100)2
    = 121/(11/10) + 121/{(11/10) x (11/10)]
    =110 + 100
    = ₹ 210