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    Question

    Length and breadth of a rectangular field is (x + 3) cm

    and (x – 5) cm, respectively. If the cost of ploughing the field at a rate of Rs. 9 per cm² is Rs. 3600, then find the cost of fencing the field at a rate of Rs. 20 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.1032 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ, Area of the field = 3600/9 = 400 cm² So, (x + 3)(x – 5) = 400 Or, x² – 2x – 400 = 0 Or, x² + 20x – 22x – 400 = 0 Or, x(x + 20) – 22(x + 20) = 0 Or, (x + 20)(x – 22) = 0 So, x = 22 Perimeter of the field = 2 × {(22 + 3) + (22 – 5)} = 86 metres Desired cost = 86 × 20 = Rs. 1720

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