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    The sum of two numbers is 72. Their HCF and LCM are 2 and 102, respectively. The sum of the reciprocals of the same two numbers is:
    Question

    The sum of two numbers is 72. Their HCF and LCM are 2 and 102, respectively. The sum of the reciprocals of the same two numbers is:

    A.

    5/17

    B.

    6/17

    C.

    7/19

    D.

    8/19

    Correct option is B

    Given:
    Sum of two numbers = 72
    HCF of the two numbers = 2
    LCM of the two numbers = 102
    Formula Used:
    a × b = HCF × LCM
    Sum of reciprocals: 1a+1b=a+ba×b \frac{1}{a} + \frac{1}{b} = \frac{a + b}{a \times b}​​
    Where a is first number and b is second number. ​
    Solution:
    Using the formula for the product of two numbers:
    a × b = HCF × LCM = 2 × 102 = 204
    So, a × b = 204
    Now,
    a + b = 72
    Now, the sum of the reciprocals of the two numbers is:
    1a+1b =a+ba×b =72204 =1234 =617\frac{1}{a} + \frac{1}{b} \\ \ \\= \frac{a + b}{a \times b} \\ \ \\= \frac{72}{204}\\ \ \\= \frac{12}{34}\\ \ \\= \frac{6}{17}​​​
    Thus, the sum of the reciprocals of the two numbers is 617. \frac{6}{17}.​​

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