New RBI Grade B 2025 Notification will come Soon! Enroll Here

    Question

    10 less than a given number K, 10 more than the given

    number K, and 38 more than the given number K are in continued proportion. Find the given number K. where K > 0.
    A 60 Correct Answer Incorrect Answer
    B 40 Correct Answer Incorrect Answer
    C 50 Correct Answer Incorrect Answer
    D 70 Correct Answer Incorrect Answer

    Solution

    Let the number be =k - 10, k + 10 and k + 38 According to the question- (k-10)/ (k + 10) = (k + 10)/ (k + 38)   (k + 10)2 = (k - 10) (k + 38)   (k² + 2 x k x 10 + 100) = (k² + 38k - 10k - 380) (k² + 20k + 100) = (k² + 28k-380) (28k-20k) = (380 + 100)   8k = 480   k = 480/8   k = 60   The value of k is 60.

    Practice Next

    Relevant for Exams: