Question

The diameter of a road roller, 120 cm long is 84 cm. If it takes 500 complete revolutions to level a playground, find the cost of levelling it at Rs. 2 per square metre.

Answer 1

Given,

• Height of Cylinderical Road Roller = 120cm = 1.2m
• Radius of Cylinderical Road Roller = 84cm/2 = 0.84m/2 = 0.42m.
• If it takes 500 complete revolutions to level a playground.
• The cost of levelling it at ₹2/m².

To Find,

• The Total Cost Of Levelling.

Solution,

→ CSA = 2 × π × r × h

→ CSA = 2 × 22/7 × 0.42m × 1.2m

→ CSA = 44/7 × 42/100 × 12/10 m²

→ CSA = (44 × 6 × 12)/1000 m²

→ CSA = 3.168m²

Area Covered in 500 Revolutions

→ 500 × 3.168m²

→ 1584m²

Required Answer,

The Total Cost = 1584m² × ₹2/m²

= ₹3168