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  1. The diameter of a 120 cm long roller is 84 cm. It takes 500 complete revolutions of the roller to level a ground. The cost of levelling the ground at Rs. 1.50 per sq. m. is :
    1. Rs. 6000
    2. Rs. 3762
    3. Rs. 2376
    4. Rs. 5750
Correct Option: C

Levelled area in one revolution of roller = 2πrh

= 2 ×
22
× 42 × 120 = 31680 sq. cm.
7

Area levelled in 500 revolutions = (31680 × 500) sq. cm. = 15840000 sq. cm.
= 1584 sq. metre
∴ Required cost = Rs. (1584 × 1.5) = Rs. 2376



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