📢 Too many exams? Don’t know which one suits you best? Book Your Free Expert 👉 call Now!


    Question

    Sum of the two numbers is 81 and their HCF and LCM are 9

    and 180, respectively. Find the sum of reciprocal of the given two numbers.
    A (1/18) Correct Answer Incorrect Answer
    B (1/15) Correct Answer Incorrect Answer
    C (1/20) Correct Answer Incorrect Answer
    D (7/18) Correct Answer Incorrect Answer

    Solution

    Let the two numbers be '9a' and '9b', where 'a' and 'b' are co-prime numbers. 9a + 9b = 81 Or, 9 X (a + b) = 81 Or, a + b = (81/9) So, a + b = 9 We know that product of two numbers = HCF of the two numbers X LCM of the two numbers Or, 9a X 9b = 9 X 180 Or, ab = (9 X 180)/(9 X 9) = 20 therefore, sum of reciprocals = (a+b)/(9ab) = 9/180 = 1/20 Hence, option c.

    Practice Next

    Relevant for Exams:

    ask-question