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    Question

    Radius of a cylinder is increased by 20% and height

    reduces by 40% so what effect on the volume of cylinder?
    A 13.6 % decreased Correct Answer Incorrect Answer
    B 12.5 % decreased Correct Answer Incorrect Answer
    C 15.6 % decreased Correct Answer Incorrect Answer
    D 14.2 % decreased Correct Answer Incorrect Answer
    E 11.6 % decreased Correct Answer Incorrect Answer

    Solution

    Radius of cylinder increased = 20 % = +1/5 Original radius = 5 unit New radius = 6 unit Height reduced = 40% = -2/5 Original Height = 5 New height = 3 Volume = π r2 h = π (5)2 x 5 = 125 π New volume = π r2 h = π (6)2 x 3 = 108 π Effect on Volume = (108 π – 125 π)/125 π x 100 = (-17 π / 125π) x 100 = 13.6 % decreased

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