Simplification


  1. (5.5)3 – (4.5)3 is equal to :









  1. View Hint View Answer Discuss in Forum

    (5.5)3 – (4.5)3
    = (5.5 – 4.5)3 + 3 × 5.5 × 4.5 (5.5 – 4.5)
    = (1)3 + 74.25 (1)
    = 1 + 74.25 = 75.25

    Correct Option: D

    (5.5)3 – (4.5)3
    = (5.5 – 4.5)3 + 3 × 5.5 × 4.5 (5.5 – 4.5)
    = (1)3 + 74.25 (1)
    = 1 + 74.25 = 75.25


  1. 3
    72.9
      is equal to :
    0.4096









  1. View Hint View Answer Discuss in Forum

    3
    72.9
    = 3
    729000
    0.40964096

    3
    (90)3
    =
    90
    (16)316

    =
    45
    = 5.625
    8

    Correct Option: B

    3
    72.9
    = 3
    729000
    0.40964096

    3
    (90)3
    =
    90
    (16)316

    =
    45
    = 5.625
    8



  1. 38
    ÷
    100
    ×3125   is equal to :
    1649









  1. View Hint View Answer Discuss in Forum

    On simplification,

    Expression =
    2
    ×
    7
    × 5
    410

    =
    7
    = 1
    3
    44

    Correct Option: B

    On simplification,

    Expression =
    2
    ×
    7
    × 5
    410

    =
    7
    = 1
    3
    44


  1. The sum of the cubes of the numbers 22, –15 and –7 is equal to









  1. View Hint View Answer Discuss in Forum

    Here, 22 – 15 – 7 = 0
    We know that
    a3 + b3 + c3 = 3abc,
    if a + b + c = 0
    ∴  (22)3 + (–15)3 + (–7)3
    = 3 × 22 × (–15) (–7) = 6930

    Correct Option: A

    Here, 22 – 15 – 7 = 0
    We know that
    a3 + b3 + c3 = 3abc,
    if a + b + c = 0
    ∴  (22)3 + (–15)3 + (–7)3
    = 3 × 22 × (–15) (–7) = 6930



  1. The least number to be subtracted from 16800 to make it a perfect square is









  1. View Hint View Answer Discuss in Forum


    ∴  Required number = 159
    16800 – 159 = 16641
    and √16641 = 129

    Correct Option: C


    ∴  Required number = 159
    16800 – 159 = 16641
    and √16641 = 129