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

    Question

    A park has a total area of 16,500 m². A cylindrical

    roller, with a radius of 7 meters and a length of 15 meters, is used to level the ground. How many complete revolutions must the roller make to cover the entire area once?
    A 74 Correct Answer Incorrect Answer
    B 84 Correct Answer Incorrect Answer
    C 70 Correct Answer Incorrect Answer
    D 25 Correct Answer Incorrect Answer
    E None of these Correct Answer Incorrect Answer

    Solution

    ATQ;
    Area levelled by the roller in one revolution = curved surface area of the roller
    = 2 × π × radius × length = 2 × (22/7) × 7 × 15 = 660 m²
    So, number of revolutions needs to level the area of the entire ground = 16500 ÷ 660 = 25

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