The diameter of a roller is 84 cm and its length 120 cm.

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The diameter of a roller is 84 cm and its length 120 cm. Its takes 500 complete revolutions to move once over to level a playground (in sq m) ?

1. 1632
2. 1817
3. 1532
4. 1584

Correct Option: D

In one revolution, area covered = Covered surface area
⇒ 2πrh = 2 x (22/7) x 42 x 120 = 31680 sq cm
in 500 revolutions,
Area covered = 31680 x 500 = (1584 x 10⁴) sq cm
= (1584 x 10⁴) / (10⁴) = 1584 sq m