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    Question

    The length, breadth and height of a room are in the

    ratio 7:5:2. If the breadth and height are halved while the length is doubled, then the total area of the four walls of the room will
    A Remains the same Correct Answer Incorrect Answer
    B will decreases by 43.75% Correct Answer Incorrect Answer
    C willl decreases by 31.25% Correct Answer Incorrect Answer
    D will decreases by 28.125% Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    Let length = 7, breadth = 5 & Height of room = 2 So original total area of four walls = 2(7 `xx` 2 + 5 `xx` 2) = 2(14 + 10) = 2 `xx` 24 = 48 Then new length = 14, new breadth = 2.5 and new height = 1 So new total area of four walls = 2(14 `xx` 1 + 2.5 `xx` 1) = 2(14 + 2.5) = 2 `xx` 16.5 = 33 ; Hence decrease in total area of four walls = (48 - 33)/48 `xx` 100 = 31.25%

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