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    Question

    Length and breadth of a rectangular field is (x + 7) cm

    and (x – 6) cm, respectively. If the cost of ploughing the field at a rate of Rs. 6 per cm² is Rs. 3888, then find the cost of fencing the field at a rate of Rs. 16 per cm.
    A Rs.1720 Correct Answer Incorrect Answer
    B Rs.1225 Correct Answer Incorrect Answer
    C Rs.1548 Correct Answer Incorrect Answer
    D Rs.1696 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Area of the field = 3888/6 = 648 cm² So, (x + 7)(x – 6) = 648 Or, x² + x – 648 = 0 Or, x² + 27x – 24x – 648 = 0 Or, x(x + 27) – 24(x + 27) = 0 Or, (x + 27)(x – 24) = 0 So, x = 24 Perimeter of the field = 2 × {(24 + 7) + (24 – 6)} = 106 metres Desired cost = 106 × 16 = Rs. 1696

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