Number System


  1. If a =16 and b= 5, the value of (a2+ b2+ ab) / (a3 - b3) is ?









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    Given Exp. = (a2+ b2+ ab) / (a3-b3)
    = 1 / (a - b)

    Correct Option: A

    Given Exp. = (a2+ b2+ ab) / (a3-b3)
    = 1 / (a - b)
    = 1 / (16 - 5)
    = 1/11.


  1. Five time of a position integer is equal to 3 less then twice the square of that number. Find the number.









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    Let the number be N
    According to the question 5N = 2N2 - 3

    Correct Option: A

    Let the number be N
    According to the question 5N = 2N2 - 3
    ⇒ 2N2 - 5N -3 = 0
    ⇒ (N - 3) (2N + 1) = 0
    N = 3 & -1/2
    Thus the required number is 3



  1. A student was asked to multiply a number by 3/2 but he divided that number by 3/2. The result was therefore 10 less then the correct answer. Find the number.









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    Let the number be N
    According to the question,
    [N x (3/2)] - [N / (3/2)] =10

    Correct Option: B

    Let the number be N
    According to the question,
    [N x (3/2)] - [N / (3/2)] =10
    ⇒ 3N/2 - 2N/3 = 10
    ⇒ (9N - 4N)/6 = 10
    ⇒ 5N / 6 = 10
    ∴ N = (10 x 6)/5 =12


  1. The sum of five consecutive odd number is equal to 175. What is the sum of the second large number and the square of the smallest number among them together?









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    Sum of the five consecutive odd number = N + (N + 2) + (N + 4) + (N + 6) + (N + 8) =175

    Correct Option: D

    Sum of the five consecutive odd number = N + (N + 2) + (N + 4) + (N + 6) + (N + 8) =175
    ⇒ 5N + 20 =175
    ⇒ N = (175 - 20) / 5 = 31

    Sum of the second largest and square of smallest one = (31 + 6) + (31)2
    = 37 + 961=998



  1. On children day sweet were to be equally distributed among 300 children. But on that particular day 50 children remain absent hence each child got one extra sweet. How many sweet were distributed ?









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    let the total number of sweet = N
    According to the question
    (N/250) - (N/300) = 1

    Correct Option: C

    let the total number of sweet = N
    According to the question
    (N/250) - (N/300) = 1
    ⇒ (6N - 5N) / 1500=1
    ∴ N = 1500