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    Question

    A hollow cylindrical pipe is made of iron. The

    difference between the outer and inner curved surface area is 176 cm². The height of the pipe is 28 cm, and the sum of the inner and outer radius is 30 cm. Find the total surface area of the hollow cylindrical pipe.
    A 3456.5 Correct Answer Incorrect Answer
    B 5468.5 Correct Answer Incorrect Answer
    C 4463.5 Correct Answer Incorrect Answer
    D 5254.5 Correct Answer Incorrect Answer

    Solution

    We have -2 π h (R-r) = 176 = 2×22/7×28(R-r) =176 R-r = 1 Also given – R + r = 30 Then – R = 15.5cm, r = 14.5cm. So, the total surface of the hollow cylinder = 2 π h(R-r) +2 π (R2-r2) =2 π (R +r) [h +R-r] =2×22/7×30(28+1) =2×22/7×30×29 =38280/7   =5468.5cm2

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