ЁЯУв Too many exams? DonтАЩt know which one suits you best? Book Your Free Expert ЁЯСЙ call Now!

    Question

    The cube of the difference between two given natural

    numbers is 1728, while the product of these two given numbers is 108. Find the positive difference between the cubes of these two given numbers.
    A 4104 Correct Answer Incorrect Answer
    B 5616 Correct Answer Incorrect Answer
    C 2160 Correct Answer Incorrect Answer
    D 5626 Correct Answer Incorrect Answer

    Solution

    1st natural number = x 2nd natural number = y (x - y)3 = 1728 (x - y) = 3тИЪ1728 = 12 ┬а┬а┬а┬а┬а┬а┬а┬а┬а┬а тАж (1) squaring both sides ┬а (x - y) ┬▓ = 144 x2+y2-2xy =144 x┬▓ + y┬▓ = 144 + 216 = 360 Now, (x + y) = тИЪ (x┬▓ + y┬▓ + 2xy) =тИЪ (360 + 216) = тИЪ576 = 24┬а┬а тАж (2) Now Eq (1) + Eq (2). x-y+x+y =12+24=36 2x =36 x=18 y=6 Now positive difference between the cubes= (18)3-(6)3 =5832-216 =5616.

    Practice Next
    More Previous year papers Questions

    Relevant for Exams:

    ask-question