Question

    type-ssc

    A hollow cylinder is made up of steel. the difference in its outer and inner curved surface area is 132cm2.Height of cylinder is 21 cm and sum of the inner and outer radius is also 21 cm. Find the Total surface of the hollow cylinder (in cm 2 )

    A 1331 Correct Answer Incorrect Answer
    B 1728 Correct Answer Incorrect Answer
    C 2904 Correct Answer Incorrect Answer
    D 1836 Correct Answer Incorrect Answer

    Solution

    We have -2 π h (R-r) = 132 = 2×22/7×21(R-r) =132 R-r = 1 Also given – R + r = 21 Then – R = 11cm, r = 10cm. So, the total surface of the hollow cylinder = 2 π h(R-r) +2 π (R2-r2) =2 π (R +r) [h +R-r] =2×22/7×21(21+1) =6×22×22 =2904cm2

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