Number System


  1. The product of two consecutive odd numbers is 19043. Which is the smaller one?









  1. View Hint View Answer Discuss in Forum

    Let the two consecutive numbers are N and N+2

    According to the question
    N (N + 2) = 19043

    Correct Option: A

    Let the two consecutive numbers are N and N+2

    According to the question
    N (N + 2) = 19043
    ⇒ N2 + 2N - 19043 = 0
    ⇒ N2 + 139N - 137N - 19043= 0
    ⇒ N( N + 139) - 137 ( N - 137 ) = 0
    ⇒ N( N + 139) ( N - 137) = 0
    ⇒ N = 137 and N = - 139
    ∴ N = 137


  1. If the three- fourth of number is subtracted from the number, the value so obtained is 163. What is that number?









  1. View Hint View Answer Discuss in Forum

    Let the number be N
    According to the question
    N - 3N/4 = 163

    Correct Option: D

    Let the number be N
    According to the question
    N - 3N/4 = 163
    ⇒ N/4 = 163
    ∴ N = 652



  1. A positive number, when increased by 10 equal 200 times its reciprocal . What is the number?









  1. View Hint View Answer Discuss in Forum

    Let the positive number be N.
    According to the question,
    N + 10 = 200/N
    ⇒ N2 + 10N = 200

    Correct Option: B

    Let the positive number be N.
    According to the question,
    N + 10 = 200/N
    ⇒ N2 + 10N = 200
    ⇒ N2 + 10N - 200 = 0
    ⇒ ( N - 10) ( N + 20) = 0
    &ythere4; N = 10 and N = -20
    But N ≠ -20, since N is a positive number.
    So, the required number is 10.


  1. The sum of two numbers is 10. Their product is 20. Find the sum of the reciprocals of the two numbers.









  1. View Hint View Answer Discuss in Forum

    Here, M + N = 10 and MN = 20
    According to the question,
    (1/M) + (1/N) = (M + N) / MN

    Correct Option: C

    Here, M + N = 10 and MN = 20
    According to the question,
    (1/M) + (1/N) = (M + N) / MN = 10/20 = 1/2



  1. Five time of a positive integer is equal to 3 less than twice the square of that number. Find the number?









  1. View Hint View Answer Discuss in Forum

    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 and N = -1/2
    Thus, the required number is 3.