New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    If the average of two numbers is 20 and the square root

    of their product is 16, then the difference between the numbers is:
    A 18 Correct Answer Incorrect Answer
    B 36 Correct Answer Incorrect Answer
    C 24 Correct Answer Incorrect Answer
    D 12 Correct Answer Incorrect Answer

    Solution

    Average of numbers = (a + b)/2 = 20 a + b = 40              ...(I) square root of these numbers = √  ab = 16 squaring both sides ab = 256 a – b =? So now – (a + b)2 = (a- b)2 + 4ab (40)2 – 4 ×256 = (a-b)2 (a-b)2 =1600- 1024 = 576   a – b = 24

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