New Enroll in RBI Grade B New Batch - Starts on May 21

    Question

    A hollow cylindrical tube 20 cm long is made of iron and

    its external and internal diameters are 8 cm and 6 cm respectively. The volume (in cubic cm) of iron used in making the tube is (Take pi; = 22/7)
    A 1760 Correct Answer Incorrect Answer
    B 440 Correct Answer Incorrect Answer
    C 220 Correct Answer Incorrect Answer
    D 880 Correct Answer Incorrect Answer

    Solution

    volume of hollow cylinder = pi;(r12 minus; r22)h h = 20 r1 (external radius) = external diameter divide;2 = 8divide;2 = 4 r2 (internal radius) = internal diameter divide;2 = 6divide;2 = 3 volume of hollow cylinder = pi;(42- 32) 20 = 22/7 (7)20 = 440

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