Number System


  1. The sum of two number is 29 and the difference of their squares is 145. The difference between the number is ?









  1. View Hint View Answer Discuss in Forum

    Let the number be a and b
    Then, (a-b) = (a2 - b2) / a+b

    Correct Option: B

    Let the number be a and b
    Then, (a-b) = (a2 - b2) / a+b
    = 145/29
    = 5


  1. The difference of two number is 5 and the difference of their squares is 135. The sum of the number is ?









  1. View Hint View Answer Discuss in Forum

    Let the number be a and b.
    Then, (a + b) = (a2 -b2) / (a-b)

    Correct Option: A

    Let the number be a and b.
    Then, (a + b) = (a2 -b2) / (a-b)
    = 135/5
    = 27



  1. If 1 is added to the denominator of fraction, the fraction becomes 1/2. If 1 is added to the numerator, the fraction becomes 1. The fraction is ?









  1. View Hint View Answer Discuss in Forum

    Let the required fraction be x/y
    Then, x/(y + 1) = 1/2
    ⇒ 2x - y = 1 ...(1)
    (x + 1) / y = 1
    ⇒ x - y = -1 ...(2)

    Correct Option: C

    Let the required fraction be x/y
    Then, x/(y + 1) = 1/2
    ⇒ 2x - y = 1 ...(1)
    (x + 1) / y = 1
    ⇒ x - y = -1 ...(2)
    Solving Eq. (1) and (2)
    We get x = 2, y = 3
    ∴ The fraction is 2/3


  1. 4/5 of a number exceeds its 2/3 by 8. The number is ?









  1. View Hint View Answer Discuss in Forum

    Let the number be x,
    Then, 4x/5 - 2x/3 = 8

    Correct Option: B

    Let the number be x,
    Then, 4x/5 - 2x/3 = 8
    ⇒ (12x - 10x) / 15 = 8
    ⇒ 2x = 120
    ∴ x = 60



  1. If one-fourth of one-third of one-half of a number is 15, the number is ?









  1. View Hint View Answer Discuss in Forum

    Let the number be N .
    Then, 1/4 of 1/3 of 1/2 of N = 15
    ⇒ 1/4 x 1/3 x 1/2 x N = 15

    Correct Option: D

    Let the number be N .
    Then, 1/4 of 1/3 of 1/2 of N = 15
    ⇒ 1/4 x 1/3 x 1/2 x N = 15
    ⇒ N/24 = 15
    ⇒ N = 24 x 15 = 360 .