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

    Question

    If (4x + 3y): (28x - y) = 1: 5, then what is the value

    of (3x 2  + 4y 2 ): (7x 2  + 2y 2 )?
    A 7:12 Correct Answer Incorrect Answer
    B 10:21 Correct Answer Incorrect Answer
    C 8:15 Correct Answer Incorrect Answer
    D None of the above Correct Answer Incorrect Answer

    Solution

    (4x + 3y): (28x - y) = 1: 5

    5(4x + 3y) = 28x - y

    20x + 15y = 28x - y

    x = 2y

    Now, (3x 2  + 4y 2 ): (7x 2  + 2y 2 )

    = (3 * (2y) 2  + 4y 2 ): (7 * (2y) 2  + 2y 2 ) = 8: 15

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