Question

7. The diameter of a roller is 42cm and length is 100cm, it takes 400 complete
revolutions moving once over to level a playground. Determine the area of the
playground? Also, find the cost of levelling the playground at Rs 2 per square
metre.​

Answer 1

Answer:

₹1,056

Step-by-step explanation:

r = 21 cm

h = 100 cm

CSA = 2πr

= 2 × 22/7 × 21 cm × 100 cm

= 44 × 300 cm²

= 13200 cm²

Number of revolutions = 400

Area covered = 400 × 13200 cm²

= 5280000 cm² = 528 m²

Given that the area covered by the roller = to the area of a playground

∴ Area of the playground is 528 m²

Cost of levelling per sq. m = ₹2

So , total cost of levelling = ₹(2 × 528) = ₹1056